Image stabilization control apparatus and imaging apparatus

ABSTRACT

An image stabilization control apparatus including a mechanism which causes a vibration when the mechanism moves is disclosed. The apparatus comprises a vibration correction unit configured to correct image shake occurring due to vibration applied to the image stabilization control apparatus. A correction value of an angular velocity of the vibration is calculated based on signals based on the angular velocity and an acceleration of the vibration, frequency bands of the signals are narrowed. During the mechanism is moving, the image shake is corrected by driving the vibration correction unit based on the angular velocity of the vibration which is corrected by the corrected value calculated before the mechanism moves.

TECHNICAL FIELD

The present invention relates to an image stabilization controlapparatus and an imaging apparatus configured to correct or preventimage shake or image degradation occurring due to vibration such as handshake.

BACKGROUND ART

In recent years, all operations of a camera significant to imagecapture, such as operation for determining the exposure and a focusingoperation, may be performed automatically. Accordingly, even a user whois not accustomed to using a camera may nearly always succeed in takinghigh quality pictures.

In addition, recently marketed cameras include an image stabilizationcontrol apparatus, which includes a vibration correction unit, a drivingunit, and a vibration detection unit and are configured to prevent imageshake occurring due to vibration. By using such recent cameras, aphotographer may nearly always succeed in taking high quality pictures.

An image stabilization control apparatus configured to prevent imageshake is briefly described below. The hand shake that may occur with acamera during capture is a vibration with a frequency of, generally 1 to10 Hz. To take a photograph without any image shake even when suchvibration is applied to a camera when the shutter release button ispressed, it is necessary to detect the vibration applied to the cameraand displace a lens for correcting image shake (hereinafter simplyreferred to as a “correction lens”) according to the detected value.

Therefore, in order to shoot an image without any image shake even whencamera undergoes vibration, it is necessary to detect a precise level ofthe vibration on the camera and to correct the variation in the opticalaxis occurring due to the vibration. The vibration (on a camera) can becalculated, in principle, by using a vibration detection unit providedon the camera. More specifically, such a vibration detection unitdetects the acceleration, the angular acceleration, the angularvelocity, and the angular displacement and executes an operation on anoutput thereof to correct image shake.

Under general capture conditions, angular vibration (rotationalvibration), which may occur according to the orientation of the camera,is the primary cause of the possible vibration. Therefore, aconventional camera includes an angular velocity meter only to detectvibration. In such a camera, it is intended that image shake besuppressed by driving a vibration correction unit (i.e., a correctionlens), which displaces the optical axis according to a signal from thevibration detection unit, with a driving unit.

Meanwhile, when an image is taken at a close distance (under a capturecondition in which a high imaging magnification is used), significantimage degradation due to parallel vibration, which may otherwise causelittle image degradation, may occur in addition to angular vibration,which may occur due to the orientation of the camera. Under captureconditions in which an object image is taken at such a close objectdistance as about 20 cm as in the case of macro photography, or if thefocal length of an imaging optical system is very large (400 mm, forexample) even when a sufficient object distance of 1 meter is secured,it becomes necessary to positively detect the parallel vibration anddrive the vibration correction unit.

In this regard, in a method discussed in Japanese Patent ApplicationLaid-Open No. 07-225405, an accelerometer configured to detectacceleration is provided to detect parallel vibration and drive avibration correction unit according to the detected parallel vibrationvalue and an output from an angular velocity meter, which is providedseparately.

Furthermore, a method discussed in Japanese Patent Application Laid-OpenNo. 2002-359769 corrects image shake while changing the amount ofcorrecting the vibration. In this method, an image sensor of a cameraacquires motion information of a captured image while correcting theimage shake. This method sets an optimum vibration correction amount byevaluating the accuracy of image shake correction according to outputfrom the image sensor.

In this regard, however, in the method discussed in Japanese PatentApplication Laid-Open No. 07-225405, output signal from theaccelerometer, which is used in detecting parallel vibration, may varydue to disturbance noise or environmental variation such as temperaturechange. Accordingly, it is difficult to correct parallel vibration withhigh accuracy.

Furthermore, in the method discussed in Japanese Patent ApplicationLaid-Open No. 2002-359769, setting an optimum vibration characteristicrequires a large amount of time. Accordingly, the user operability ofthe camera may be degraded. In addition, mechanical parts of thevibration correction unit become large to achieve a variable vibrationcorrection amount.

DISCLOSURE OF INVENTION

The present invention provides a small-sized image stabilization controlapparatus with high operability and high correction accuracy of imageshake due to parallel vibration, and a control method therefor.

According to an aspect of the present invention, there is provided animage stabilization control apparatus having an instruction unit toallow a user to instruct the image stabilization control apparatus toexecute image capture preparation operations and image captureoperations, comprising: a vibration correction unit configured tocorrect image shake occurring due to vibration applied to the imagestabilization control apparatus; a first vibration detection unitconfigured to detect and output an angular velocity of the vibration; asecond vibration detection unit configured to detect and output anacceleration of the vibration; a calculation unit configured tocalculate a correction value based on the outputs of the first andsecond vibration detection units; an output correction unit configuredto correct the output of the first vibration detection unit using thecorrection value and to output the corrected output; and a driving unitconfigured to drive the vibration correction unit based on either theoutput of the first vibration detection unit or the output of the outputcorrection unit, wherein, during the image capture operations, theoutput correction unit being configured to correct the output of thefirst vibration detection unit using the correction value calculatedbefore an execution of the image capture operations is instructed by theinstruction unit.

According to another aspect of the present invention, there is providedan image stabilization control apparatus including an imaging opticalsystem whose imaging magnification is variable and an instruction unitto allow a user to instruct the image stabilization control apparatus toexecute image capture preparation operations and image captureoperations, the image stabilization control apparatus comprising: avibration correction unit configured to correct image shake occurringdue to vibration applied to the image stabilization control apparatus; afirst vibration detection unit configured to detect and output anangular velocity of the vibration; a second vibration detection unitconfigured to detect and output an acceleration of the vibration; acalculation unit configured to calculate a correction value based on theoutputs of the first and second vibration detection units; an outputcorrection unit configured to correct the output of the first vibrationdetection unit using the correction value and to output the correctedoutput; and a driving unit configured to drive the vibration correctionunit based on either the output of the first vibration detection unit orthe output of the output correction unit, a principal point movementdetection unit configured to detect and output a change of a principalpoint of the imaging optical system due to a change of the imagingmagnification; and a correction value correction unit configured tocorrect the correction value based on an output of the principal pointmoving detection unit.

According to further aspect of the present invention, there is providedan image stabilization control apparatus having an instruction unit toallow a user to instruct the image stabilization control apparatus toexecute image capture preparation operations and image captureoperations, the image stabilization control apparatus comprising: avibration correction unit configured to correct image shake occurringdue to vibration applied to the image stabilization control apparatus; afirst vibration detection unit configured to detect and output anangular velocity of the vibration; a second vibration detection unitconfigured to detect and output an acceleration of the vibration; acalculation unit configured to calculate a correction value based on theoutputs of the first and second vibration detection units; an outputcorrection unit configured to correct the output of the first vibrationdetection unit using the correction value and to output the correctedoutput; and a driving unit configured to drive the vibration correctionunit based on either the output of the first vibration detection unit orthe output of the output correction unit, a reliability determinationunit configured to determine reliability of the correction value,wherein if it is determined by the reliability determination unit thatthe reliability is low, the output correction unit is configured to usea previously stored correction value to correct the output of the firstvibration detection unit.

According to yet further aspect of the present invention, there isprovided an imaging apparatus having an instruction unit to allow a userto instruct the image stabilization control apparatus to execute imagecapture preparation operations and image capture operations, the imagingapparatus comprising: an image sensor; a vibration correction unitconfigured to correct image shake occurring due to vibration applied tothe imaging apparatus; a first vibration detection unit configured todetect and output an angular velocity of the vibration; a secondvibration detection unit configured to detect and output a displacementof the vibration based on a motion vector between two chronologicallycontinuous images from the imaging unit; a calculation unit configuredto calculate a correction value based on either the output of the firstvibration detection unit or the outputs of the first and secondvibration detection units; an output correction unit configured tocorrect the output of the first vibration detection unit using thecorrection value and to output the corrected output; and a driving unitconfigured to drive the vibration correction unit based on either theoutput of the first vibration detection unit or the output of the outputcorrection unit.

According to still further aspect of the present invention, there isprovided an imaging apparatus including an imaging unit, an imagingoptical system whose imaging magnification is variable, and aninstruction unit to allow a user to instruct the image stabilizationcontrol apparatus to execute image capture preparation operations andimage capture operations, the imaging apparatus comprising: an imagesensor; a vibration correction unit configured to correct image shakeoccurring due to vibration applied to the imaging apparatus; a firstvibration detection unit configured to detect and output an angularvelocity of the vibration; a second vibration detection unit configuredto detect and output a displacement of the vibration based on a motionvector between two chronologically continuous images from the imagingunit; a calculation unit configured to calculate a correction valuebased on the outputs of the first and second vibration detection units;an output correction unit configured to correct the output of the firstvibration detection unit using the correction value and to output thecorrected output; a driving unit configured to drive the vibrationcorrection unit based on either the output of the first vibrationdetection unit or the output of the output correction unit; a principalpoint movement detection unit configured to detect and output a changeof a principal point of the imaging optical system due to a change ofthe imaging magnification; and a correction value correction unitconfigured to correct the correction value based on an output of theprincipal point movement detection unit.

According to another aspect of the present invention, there is providedan imaging apparatus having an instruction unit to allow a user toinstruct the image stabilization control apparatus to execute imagecapture preparation operations and image capture operations, the imagingapparatus comprising: an image sensor; a vibration correction unitconfigured to correct image shake occurring due to vibration applied tothe imaging apparatus; a first vibration detection unit configured todetect and output an angular velocity of the vibration; a secondvibration detection unit configured to detect and output a displacementof the vibration based on a motion vector between two chronologicallycontinuous images from the imaging unit; a calculation unit configuredto calculate a correction value based on either the output of the firstvibration detection unit or the outputs of the first and secondvibration detection units; an output correction unit configured tocorrect the output of the first vibration detection unit using thecorrection value and to output the corrected output; a driving unitconfigured to drive the vibration correction unit based on either theoutput of the first vibration detection unit or the output of the outputcorrection unit; and a reliability determination unit configured todetermine reliability of the correction value, wherein if it isdetermined by the reliability determination unit that the reliability islow, the output correction unit is configured to use a previously storedcorrection value to correct the output of the first vibration detectionunit.

According to another aspect of the present invention, there is providedan image stabilization control apparatus comprising: a vibrationcorrection unit configured to correct image shake occurring due tovibration applied to the image stabilization control apparatus; a firstvibration detection unit configured to detect and output an angularvelocity of the vibration; a second vibration detection unit configuredto detect and output an acceleration of the vibration; a calculationunit configured to calculate a correction value based on the output fromthe first vibration detection unit and the output from the secondvibration detection unit; an output correction unit configured tocorrect the output of the first vibration detection unit, the outputcorrection unit being configured to correct the output of the firstvibration detection unit using the correction value calculated; and adriving unit configured to drive the vibration correction unit based onthe output of the first vibration detection unit corrected by the outputcorrection unit.

According to another aspect of the present invention, there is providedan image stabilization control apparatus including an imaging opticalsystem whose imaging magnification is variable and a mechanism whichcauses a vibration when the mechanism moves, the image stabilizationcontrol apparatus comprising: a vibration correction unit configured tocorrect image shake occurring due to vibration applied to the imagestabilization control apparatus; a first vibration detection unitconfigured to detect and output an angular velocity of the vibration; asecond vibration detection unit configured to detect and output anacceleration of the vibration; a calculation unit configured tocalculate a correction value based on the output from the firstvibration detection unit and the output from the second vibrationdetection unit; an output correction unit configured to correct theoutput of the first vibration detection unit, the output correction unitbeing configured to correct the output of the first vibration detectionunit using the correction value calculated before the mechanism startsto move during the mechanism is moving; a driving unit configured todrive the vibration correction unit based on the output of the firstvibration detection unit corrected by the output correction unit; aprincipal point movement detection unit configured to detect and outputa relative change of a principal point of the imaging optical system;and a correction value correction unit configured to correct thecorrection value based on an output of the principal point movingdetection unit.

According to another aspect of the present invention, there is providedan image stabilization control apparatus including a mechanism whichcauses a vibration when the mechanism moves, the image stabilizationcontrol apparatus comprising: a vibration correction unit configured tocorrect image shake occurring due to vibration applied to the imagestabilization control apparatus; a first vibration detection unitconfigured to detect and output an angular velocity of the vibration; asecond vibration detection unit configured to detect and output anacceleration of the vibration; a calculation unit configured tocalculate a correction value based on the output from the firstvibration detection unit and the output from the second vibrationdetection unit; an output correction unit configured to correct theoutput of the first vibration detection unit, the output correction unitbeing configured to correct the output of the first vibration detectionunit using the correction value calculated before the mechanism startsto move during the mechanism is moving; a driving unit configured todrive the vibration correction unit based on the output of the firstvibration detection unit corrected by the output correction unit; and areliability determination unit configured to determine reliability ofthe correction value, wherein if it is determined by the reliabilitydetermination unit that the reliability is low, the output correctionunit is configured to use a previously stored correction value tocorrect the output of the first vibration detection unit.

According to another aspect of the present invention, there is providedan imaging apparatus including an imaging unit and a mechanism whichcauses a vibration when the mechanism moves, the imaging apparatuscomprising: a vibration correction unit configured to correct imageshake occurring due to vibration applied to the imaging apparatus; afirst vibration detection unit configured to detect and output anangular velocity of the vibration; a second vibration detection unitconfigured to detect and output a displacement of the vibration based ona motion vector between two chronologically continuous images from theimaging unit; a calculation unit configured to calculate a correctionvalue based on the output from the first vibration detection unit andthe output from the second vibration detection unit; an outputcorrection unit configured to correct the output of the first vibrationdetection unit, the output correction unit being configured to correctthe output of the first vibration detection unit using the correctionvalue calculated before the mechanism starts to move during themechanism is moving; and a driving unit configured to drive thevibration correction unit based on the output of the first vibrationdetection unit corrected by the output correction unit.

According to another aspect of the present invention, there is providedan imaging apparatus including an imaging unit, an imaging opticalsystem whose imaging magnification is variable, and a mechanism whichcauses a vibration when the mechanism moves, the imaging apparatuscomprising: a vibration correction unit configured to correct imageshake occurring due to vibration applied to the imaging apparatus; afirst vibration detection unit configured to detect and output anangular velocity of the vibration; a second vibration detection unitconfigured to detect and output a displacement of the vibration based ona motion vector between two chronologically continuous images from theimaging unit; a calculation unit configured to calculate a correctionvalue based on the output from the first vibration detection unit andthe output from the second vibration detection unit; an outputcorrection unit configured to correct the output of the first vibrationdetection unit, the output correction unit being configured to correctthe output of the first vibration detection unit using the correctionvalue calculated before the mechanism starts to move during themechanism is moving; a driving unit configured to drive the vibrationcorrection unit based on the output of the first vibration detectionunit corrected by the output correction unit; a principal point movementdetection unit configured to detect and output a relative change of aprincipal point of the imaging optical system; and a correction valuecorrection unit configured to correct the correction value based on anoutput of the principal point movement detection unit.

According to another aspect of the present invention, there is providedan imaging apparatus including an imaging unit and a mechanism whichcauses a vibration when the mechanism moves, the imaging apparatuscomprising: a vibration correction unit configured to correct imageshake occurring due to vibration applied to the imaging apparatus; afirst vibration detection unit configured to detect and output anangular velocity of the vibration; a second vibration detection unitconfigured to detect and output a displacement of the vibration based ona motion vector between two chronologically continuous images from theimaging unit; a calculation unit configured to calculate a correctionvalue based on the output from the first vibration detection unit andthe output from the second vibration detection unit; an outputcorrection unit configured to correct the output of the first vibrationdetection unit, the output correction unit being configured to correctthe output of the first vibration detection unit using the correctionvalue calculated before the mechanism starts to move during themechanism is moving; a driving unit configured to drive the vibrationcorrection unit based on the output of the first vibration detectionunit corrected by the output correction unit; and a reliabilitydetermination unit configured to determine reliability of the correctionvalue, wherein if it is determined by the reliability determination unitthat the reliability is low, the output correction unit is configured touse a previously stored correction value to correct the output of thefirst vibration detection unit.

According to another aspect of the present invention, there is providedan imaging apparatus comprising the image stabilization controlapparatus according to the present invention.

Further features and aspects of the present invention will be apparentfrom the following detailed description of exemplary embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate exemplary embodiments, features,and aspects of the invention and together with the description, serve toexplain the principles of the present invention.

FIG. 1 is a plan view illustrating an example of a single-lens reflexcamera according to a first exemplary embodiment of the presentinvention.

FIG. 2 is a side view illustrating an example of the single-lens reflexcamera according to the first exemplary embodiment of the presentinvention.

FIG. 3 illustrates an example of an image stabilization controlapparatus included in the single-lens reflex camera according to thefirst exemplary embodiment of the present invention.

FIG. 4 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 5 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 6 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 7 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 8 illustrates exemplary waveforms in the image stabilizationcontrol apparatus according to the first exemplary embodiment of thepresent invention.

FIG. 9 illustrates exemplary waveforms in the image stabilizationcontrol apparatus according to the first exemplary embodiment of thepresent invention.

FIG. 10 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 11 illustrates exemplary vibration of a camera according to thefirst exemplary embodiment of the present invention.

FIG. 12 illustrates an example of an accelerometer according to thefirst exemplary embodiment of the present invention.

FIG. 13 illustrates an exemplary frequency characteristic of theaccelerometer according to the first exemplary embodiment of the presentinvention.

FIG. 14 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 15 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 16 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 17 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 18 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 19 illustrates another exemplary configuration of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 20 illustrates an exemplary frequency characteristic for arotational radius in the image stabilization control apparatus accordingto the first exemplary embodiment of the present invention.

FIG. 21 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 22 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 23 illustrates an exemplary frequency characteristic of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 24 illustrates a further exemplary configuration of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 25 is a block diagram illustrating a further exemplaryconfiguration of the image stabilization control apparatus according tothe first exemplary embodiment of the present invention.

FIG. 26 illustrates a further exemplary configuration of the imagestabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 27 illustrates exemplary waveforms in the image stabilizationcontrol apparatus according to the first exemplary embodiment of thepresent invention.

FIG. 28 illustrates exemplary waveforms in the image stabilizationcontrol apparatus according to the first exemplary embodiment of thepresent invention.

FIG. 29 illustrates exemplary waveforms in the image stabilizationcontrol apparatus according to the first exemplary embodiment of thepresent invention.

FIG. 30 is a timing chart illustrating an exemplary operation of theimage stabilization control apparatus according to the first exemplaryembodiment of the present invention.

FIG. 31 illustrates exemplary vibration of a camera according to thefirst exemplary embodiment of the present invention.

FIG. 32 is a flow chart illustrating an exemplary operation of maincomponents of the image stabilization control apparatus according to thefirst exemplary embodiment of the present invention.

FIG. 33 illustrates an example of a signal processing system that drivesa vibration correction unit according to the first exemplary embodimentof the present invention.

FIG. 34 illustrates an exemplary waveform for driving the vibrationcorrection unit according to the first exemplary embodiment of thepresent invention.

FIG. 35 illustrates an exemplary waveform of an output from theaccelerometer according to the first exemplary embodiment of the presentinvention.

FIG. 36 illustrates exemplary vibration of a camera according to thefirst exemplary embodiment of the present invention.

FIG. 37 illustrates exemplary vibration of a camera according to thefirst exemplary embodiment of the present invention.

FIG. 38 illustrates an exemplary inner configuration of an outputcorrection unit according to the first exemplary embodiment of thepresent invention.

FIG. 39 illustrates an exemplary configuration of an image stabilizationcontrol apparatus according to a second exemplary embodiment of thepresent invention.

FIG. 40 is a timing chart illustrating a moving average of a rotationalradius of the image stabilization control apparatus according to thesecond exemplary embodiment of the present invention.

FIG. 41 illustrates another exemplary configuration of the imagestabilization control apparatus according to the second exemplaryembodiment of the present invention.

FIG. 42 illustrates an exemplary waveform for an output of accelerationaccording to the second exemplary embodiment of the present invention.

FIG. 43 is a flow chart illustrating exemplary processing forcontrolling the accelerometer according to the second exemplaryembodiment of the present invention.

FIG. 44 is a flow chart illustrating an exemplary operation of the imagestabilization control apparatus according to the second exemplaryembodiment of the present invention.

FIG. 45 is a timing chart illustrating an example of an operation of theimage stabilization control apparatus according to the second exemplaryembodiment of the present invention.

FIG. 46 illustrates an example of vibration of a camera according to thesecond exemplary embodiment of the present invention.

FIG. 47 illustrates an example of vibration of a camera according to thesecond exemplary embodiment of the present invention.

FIG. 48 illustrates an exemplary configuration of an image stabilizationcontrol apparatus according to a third exemplary embodiment of thepresent invention.

FIG. 49 illustrates an exemplary waveform of an output of accelerationaccording to the third exemplary embodiment of the present invention.

FIG. 50 illustrates exemplary waveforms for vibration used in the imagestabilization control apparatus according to the third exemplaryembodiment of the present invention.

FIG. 51 illustrates exemplary waveforms for vibration in the imagestabilization control apparatus according to the third exemplaryembodiment of the present invention.

FIG. 52 illustrates exemplary waveforms for vibration in the imagestabilization control apparatus according to the third exemplaryembodiment of the present invention.

FIG. 53 illustrates another exemplary configuration of the imagestabilization control apparatus according to the third exemplaryembodiment of the present invention.

FIG. 54 illustrates an exemplary configuration of an image stabilizationcontrol apparatus according to a fourth exemplary embodiment of thepresent invention.

FIG. 55 illustrates an exemplary waveform of an output from theaccelerometer according to the fourth exemplary embodiment of thepresent invention.

FIG. 56 illustrates an exemplary configuration of an image stabilizationcontrol apparatus according to a fifth exemplary embodiment of thepresent invention.

FIG. 57 illustrates an exemplary configuration of an image stabilizationcontrol apparatus according to a sixth exemplary embodiment of thepresent invention.

FIGS. 58A through 58H each illustrate an orientation of a cameraaccording to the sixth exemplary embodiment of the present invention.

FIG. 59 illustrates an exemplary configuration of an image stabilizationcontrol apparatus according to a seventh exemplary embodiment of thepresent invention.

FIG. 60 is a block diagram illustrating an exemplary configuration of animage stabilization control apparatus according to an eighth exemplaryembodiment of the present invention.

FIG. 61 illustrates an exemplary configuration of a camera and an imagestabilization control apparatus according to a ninth exemplaryembodiment of the present invention.

FIGS. 62A and 62B each illustrate an exemplary configuration of avibration correction unit according to the ninth exemplary embodiment ofthe present invention.

FIG. 63 is a flow chart illustrating an exemplary operation of the imagestabilization control apparatus according to the ninth exemplaryembodiment of the present invention.

FIG. 64 illustrates an exemplary configuration of a camera and an imagestabilization control apparatus according to a tenth exemplaryembodiment of the present invention.

FIG. 65 illustrates an example of motion vectors according to the tenthexemplary embodiment of the present invention.

FIG. 66 illustrates exemplary waveforms for vibration in the imagestabilization control apparatus according to the tenth exemplaryembodiment of the present invention.

FIG. 67 illustrates another exemplary configuration of the camera andthe image stabilization control apparatus according to the tenthexemplary embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Various exemplary embodiments, features, and aspects of the presentinvention are described in detail below with reference to the drawings.The relative arrangement of the components, the numerical expressions,and numerical values set forth in these embodiments are not intended tolimit the scope of the present invention.

A first exemplary embodiment of the present invention is describedbelow. FIGS. 1 and 2 are a plan view and a side view illustrating anexample of a single-lens reflex camera having an image stabilizationcontrol apparatus according to the present exemplary embodiment.

Referring to FIG. 1, an exchangeable photographic lens 6801 having avibration correction unit is mounted on a camera body 6804. Thevibration correction unit is described in detail below. To brieflydescribe the vibration correction unit, the vibration correction unitexecutes correction of image shake such as vibration occurring in avertical or horizontal direction of an optical axis 6082. The vibrationoccurring in a vertical or horizontal direction of an optical axis ishereinafter simply and collectively referred to as “angular vibration”.The angular vibration is indicated by arrows 6803 p and 6803 y in FIGS.1 and 2.

In the present exemplary embodiment, reference symbol “p” is added to areference number indicating vibration of the camera which may occur in adirection vertical to the camera body 6804 (in a pitch directionindicated by arrows 6806 p and 101 pb in FIGS. 1 and 2). On the otherhand, reference symbol “y” is added to a reference number indicatingvibration of the camera which may occur in a direction horizontal to thecamera body 6804 (in a yaw direction indicated by arrows 6806 y and 101yb in FIGS. 1 and 2).

In addition, the camera body 6804 includes a release button 6804 a, amode dial 6804 b (including a main switch), a retractable flash unit6804 c, a camera central processing unit (CPU) 6804 d, and an imagesensor 6805. Furthermore, a vibration correction unit 6806 includes acorrection lens 6806 a, a coil, and a permanent magnet. A driving unitsupplies current to the coil. The driving unit is described in detailbelow. A frontmost lens 6810, the correction lens 6806 a, andnon-specified lenses together construct an imaging optical system ofwhich imaging magnification is variable. The correction lens 6806 a canfreely move in the direction indicated by the arrows 6806 p and 6806 yby the effect of the coil and the permanent magnet. Thus, image shakeoccurring in directions indicated by arrows 6803 p and 6803 y can becorrected.

Angular velocity meters (hereinafter referred to as “gyros”) 6807 p and6807 y each detect vibration occurring at portions around arrows 6803 pand 6803 y. The gyros 6807 p and 6807 y have detection sensitivitydirections indicated by arrows 6807 pa and 6807 ya. An output of angularvelocity detected by the gyros 6807 p and 6807 y is calculated by a lensCPU 6808. The lens CPU 6808 converts the input angular velocity outputinto a driving target value for the vibration correction unit 6806(i.e., the correction lens 6806 a).

When a user half-presses the release button 6804 a provided on thecamera body 6804 (i.e., when the user presses a switch S1 to executecapture preparation operations such as a photometry operation and afocusing operation), a driving target value is input to a driving unit(driver) 6809. Furthermore, the driving unit 6809 drives the coil of thevibration correction unit 6806. Accordingly, as described above, thecorrection lens 6806 a can be moved in the direction of correcting imageshake on a plane orthogonal to the optical axis by the effect of thecoil and the permanent magnet (in the direction indicated by the arrows6806 p and 6806 y in FIGS. 1 and 2). Thus, the correction of the imageshake in the direction of the arrows 6803 p and 6803 y begins.

The image stabilization control apparatus includes the vibrationcorrection unit 6806, the gyros 6807 p and 6807 y, the lens CPU 6808,and the driving unit 6809.

A conventional image stabilization control apparatus uses the gyros 6807p and 6807 y to detect vibration such as hand shake. However, inaddition to the angular vibration occurring around the arrows 6803 p and6803 y, translational vibration (hereinafter simply referred to as“parallel vibration”) is applied to the camera body 6804 as illustratedwith arrows 101 pb and 101 yb. Accordingly, translational movement at aprincipal point of the lens may become one of the causes of image shake.

Under a general capture condition, angular vibration (rotationalvibration) occurring around a portion indicated by the arrows 6803 p and6803 y dominantly and primarily occurs while only a small level of imagedegradation may occur due to parallel vibration indicated by the arrows101 pb and 101 yb. Accordingly, in this case, it is necessary to provideonly the gyros 6807 p and 6807 y are sufficient to detect vibration.

On the other hand, the present exemplary embodiment includes, inaddition to the gyros 6807 p and 6807 y, accelerometers (hereinafterreferred to as “ACCs”) 101 p and 101 y, which are configured to detectthe acceleration, as a vibration detection unit configured to detect theparallel vibration applied to the camera (the image stabilizationcontrol apparatus), which is indicated by the arrows 101 pb and 101 ybin FIGS. 1 and 2.

Arrows 101 pa and 101 ya indicate the acceleration detection centers ofthe ACCs 101 p and 101 y, respectively. The outputs from the gyros 6807p and 6807 y and the ACCs 101 p and 101 y are input to the lens CPU6808. The driving unit 6809 drives the vibration correction unit 6806according to the outputs.

FIG. 3 is a block diagram illustrating an example of the imagestabilization control apparatus according to the present exemplaryembodiment. In the example illustrated in FIG. 3, the exemplaryconfiguration in the pitch direction only is described, but a similarconfiguration is provided in the yaw direction of the camera. Theconfigurations are essentially the same as each other. Accordingly, inthe following description, the configuration is only described in thepitch direction.

The correction of the angular vibration is described in detail belowwith reference to FIG. 3. A signal of angular velocity from the gyro6807 p is input to the lens CPU 6808. Then, the angular velocity signalis input to a high-pass filter (HPF) integration filter 301. The HPFintegration filter 301 filters out direct current (DC) components fromthe angular velocity signal and integrates the filtered signal toconvert the angular velocity signal into an angular signal. The HPFprocessing and the integration can be implemented by executing anarithmetic operation within the lens CPU 6808. A publicly knowndifference equation can be used for the HPF processing and theintegration. Alternatively, it is also useful if the HPF processing andthe integration are implemented by an analog circuit by utilizingcapacitors or resistors before the signal is input to the lens CPU 6808.

In the present exemplary embodiment, the frequency band of vibrationranges from 1 to 10 Hz. Accordingly, the HPF integration filter 301 hasa first-order HPF characteristic for filtering out frequency componentsof 0.1 Hz or lower, which value is sufficiently different from thefrequency band of vibration. This HPF characteristic of the HPFintegration filter 301 is hereinafter simply referred to as “0.1Hz-break frequency first-order HPF processing”.

FIGS. 4 and 5 are Bode diagrams each illustrating the HPF characteristicthat includes the “0.1 Hz-break frequency first-order HPF processing”.In FIGS. 4 and 5, a frequency is shown on the horizontal axis while again and a phase are shown on the vertical axis. An arrow 404 indicatesthe vibration frequency band. With respect to the gain, an output ratioof the HPF integration filter 301 to the output from the gyro 6807 p isindicated in units of decibels (db).

In the present exemplary embodiment, in “1 Hz break-frequencyfirst-order HPF processing” illustrated in FIG. 4, the frequency of again 401 of 1 Hz or less is filtered out. However, the gain isattenuated by 6 db at a vibration lower limit frequency of 1 Hz.Furthermore, at 1 Hz, a phase 402 leads by 45 degrees as illustratedwith an arrow 403. More specifically, vibration of 1 Hz cannot bedetected with high accuracy. Accordingly, in this case, image shake maynot be optimally corrected.

On the other hand, in the case of “0.1 Hz break-frequency first-orderHPF processing” illustrated in FIG. 5, the gain 501 has been slightlyattenuated at the vibration lower limit frequency of 1 Hz while a phase502 leads as small an angle as 5 degrees at 1 Hz as illustrated with anarrow 503. Accordingly, in this case, image shake can be corrected forthe vibration at 1 Hz with high accuracy.

The same applies to the integration. More specifically, in the presentexemplary embodiment, the vibration frequency band ranges from 1 to 10Hz. Accordingly, the HPF integration filter 301 has an integrationcharacteristic of integrating a frequency component of 0.1 Hz or higher,which is sufficiently different from the vibration frequency band, inthe first order. This integration characteristic of the HPF integrationfilter 301 is hereinafter simply referred to as “0.1 Hz-break frequencyfirst-order integration processing”.

FIGS. 6 and 7 are Bode diagrams each illustrating the integrationcharacteristic that includes the “0.1 Hz-break frequency first-orderintegration processing”. In FIGS. 6 and 7, a frequency is shown on thehorizontal axis while a gain and a phase are shown on the vertical axis.The arrow 404 indicates the vibration frequency band. With respect tothe gain, an output ratio of the HPF integration filter 301 to theoutput from the gyro 6807 p is indicated in units of decibels (db).

In the present exemplary embodiment, by executing “1 Hz break-frequencyfirst-order integration processing” illustrated in FIG. 6, a first-orderintegration characteristic in which a gain 601 is attenuated inproportion to the frequency in the frequency range of 1 Hz or higher isacquired. However, the gain is attenuated by 6 db at a vibration lowerlimit frequency of 1 Hz.

Furthermore, at 1 Hz, a phase 602 leads by 45 degrees as illustratedwith an arrow 603. More specifically, vibration of 1 Hz cannot bedetected with high accuracy. Accordingly, in this case, image shakecannot be sufficiently corrected.

The cause of the attenuation of the gain by 6 db at 1 Hz is describedmore specifically . The gain is −16 db at a frequency not to beintegrated, such as 0.01 Hz or 0.1 Hz. If the integration starts fromthe gain at 1 Hz, the amount of attenuation of gain should be 16 db at 1Hz. However, the gain is actually −22 db at 1 Hz. That is, the gain isattenuated by additional 6 db at 1 Hz.

On the other hand, in “0.1 Hz break-frequency first-order integrationprocessing” illustrated in FIG. 7, a gain 701 is attenuated by a smallamount at the vibration lower limit frequency of 1 Hz. A phase 702advances by 5 degrees only at 1 Hz as illustrated with an arrow 703.Accordingly, in this case, image shake can be corrected for thevibration at 1 Hz with high accuracy.

The above-described vibration correction processing is described indetail below with reference to waveforms of actual vibration, vibrationdetected by the gyro 6807 p, and uncorrected vibration.

FIG. 8 illustrates the waveforms of vibration and results of executingthe “1 Hz break-frequency first-order HPF processing” and the “1 Hzbreak-frequency first-order integration processing”. In the exampleillustrated in FIG. 8, time is shown on the horizontal axis. An actualvibration angle, an angular velocity of the vibration detected by thegyro 6807 p, an angular velocity of the vibration after HPF processing,an integration angle calculated by integrating an angular velocityoutput after HPF processing, and uncorrected vibration, which is thedifference between the actual vibration angle and the integration angle,are respectively shown on a vertical axis of charts from top to bottom.

Referring to FIG. 8, a waveform 801 indicates a vibration angle of 1 Hz,which is a lower limit frequency for actual vibration. A waveform 802indicates the angular velocity detected by the gyro 6807 p when thevibration is input. In an actual output of the gyro 6807 p, a DC biascomponent and a long-term drift component are superposed. Accordingly, awaveform 803 is acquired when the above-described noise component isattenuated by executing the “1 Hz break-frequency first-order HPFprocessing”.

The amplitude of the waveform 803 is attenuated to a half of that of thewaveform 802 and the phase of the waveform 803 advances by 45 degrees.This phenomenon occurs because the waveform at 1 Hz, which is thevibration lower limit frequency, has been subjected to the “1 Hzbreak-frequency first-order HPF processing”.

A waveform 804 is acquired when the above-described waveform 803 issubjected to the “1 Hz break-frequency first-order integrationprocessing”. Due to a cause similar to the above-described cause, theamplitude is attenuated to one half the amplitude of the waveform 803and the phase is displaced. Compared to the actual vibration anglewaveform 801, the amplitude has been considerably attenuated and thephase leads by 90 degrees.

More specifically, the phase leads by 90 degrees as described abovebecause the phase leads by 45 degrees by the first-order HPF and hasfurther advanced by 45 degrees by the first-order integration, andaccordingly, the phase leads by 90 degrees in total.

A waveform 805 refers to uncorrected vibration, which is the differencebetween the actual vibration and the integration angle, which iscalculated by operating the actual vibration angle waveform 801. Theamplitude of the waveform 805 does not greatly differ from that of theactual vibration angle waveform 801. Accordingly, image shake at thisfrequency may be corrected in a small amount.

FIG. 9 illustrates exemplary waveforms acquired when the “0.1 Hzbreak-frequency first-order HPF processing” and the “0.1 Hzbreak-frequency first-order integration processing” are executed.

In the example illustrated in FIG. 9 also, time is shown on thehorizontal axis. An actual vibration angle, an angular velocity of thevibration detected by the gyro 6807 p, an angular velocity of thevibration after HPF processing, an integration angle calculated byintegrating an angular velocity output after HPF processing, anduncorrected vibration, which is the difference between the actualvibration angle and the integration angle, are shown on the respectivevertical axis of charts from top to bottom.

Referring to FIG. 9, a waveform 901 indicates a vibration angle at 1 Hz,which is a lower limit frequency of actual vibration. A waveform 902indicates the angular velocity detected by the gyro 6907 p when thevibration is input. In an actual output of the gyro 6907 p, a DC biascomponent and a long-term drift component are superposed. Accordingly, awaveform 903 is acquired when the above-described noise component isattenuated by executing the “0.1 Hz break-frequency first-order HPFprocessing”.

The amplitude of the waveform 903 does not differ greatly from that ofthe waveform 902. The phase has only advanced by 5 degrees from that ofthe waveform 902. This is because, as described above, the angularvelocity signal has been processed by executing the “0.1 Hzbreak-frequency first-order HPF processing,” whose frequency issufficiently lower than the vibration lower limit frequency of 1 Hz.

A waveform 904 is acquired when the above-described waveform 903 issubjected to the “0.1 Hz break-frequency first-order integrationprocessing.” Due to a cause similar to the cause described above, theamplitude of the waveform 904 has been attenuated by only a smallamount. Furthermore, the phase of the waveform 904 leads by only 10degrees compared to the actual vibration angle waveform 901. The phaseleads by 10 degrees in total because the phase advances by 5 degrees byexecuting the first-order HPF processing and further advances by 5degrees when the integration is executed.

A waveform 905 refers to uncorrected vibration, which is the differencebetween the actual vibration and the integration angle, which iscalculated by operating the actual vibration angle waveform 901. Theamplitude of the waveform 905 has been attenuated approximately to aquarter of the amplitude of the actual vibration angle waveform 901.Accordingly, image shake can be effectively corrected by executing theHPF processing and the integration also in a frequency rangesufficiently lower than the vibration lower limit frequency.

Returning to FIG. 3, an output from the HPF integration filter 301 (anangular signal θ) is input to a sensitivity adjustment unit 303. Thesensitivity adjustment unit 303 amplifies the output from the HPFintegration filter 301 according to zoom and focus information 302,which is input to the lens CPU 6808 from a focus encoder or a zoomencoder, and an imaging magnification that can be calculated accordingto the zoom and focus information 302. Furthermore, the sensitivityadjustment unit 303 sets the amplified output from the HPF integrationfilter 301 as an angular vibration correction target value.

The amplified output from the HPF integration filter 301 is used as anangular vibration correction target value as described above in order tocorrect a varied vibration correction sensitivity on an image plane ofthe camera to a vibration correction stroke of the vibration correctionunit 6806, which has varied due to variation in an optical state such asa focusing state or a zoom state of the lens.

The lens CPU 6808 outputs the calculated angular vibration correctiontarget value to the driving unit 6809 to drive the vibration correctionunit 6806. Accordingly, image shake is corrected. The present exemplaryembodiment corrects angular vibration in the above-described manner.

In the present exemplary embodiment, the vibration correction unit 6806is driven by using a value calculated by adding a parallel vibrationcorrection target value (to be described later below) to the angularvibration correction target value.

FIG. 10 illustrates an example of a frequency characteristic of theentire vibration correction processing. In the example illustrated inFIG. 10, time is shown on the horizontal axis. A gain 1001, whichindicates a ratio of a correction operation by the vibration correctionunit 6806 to the angle of vibration in units of db, and a phase 1002thereof are shown on the vertical axis.

In the examples illustrated in FIGS. 6 and 7, a vibration angularvelocity is compared with an integral value thereof and the frequencycharacteristic of the integral value is described. Accordingly, in theexamples illustrated in FIGS. 6 and 7, the gains 601 and 701 areattenuated in proportion to the frequency and the phases 602 and 702delay by 90 degrees within the vibration frequency band 404.

On the other hand, in the example illustrated in FIG. 10, a vibrationangle is compared with an angular vibration correction target value andthe frequency characteristic of the angular vibration correction targetvalue (a vibration angle acquired by operating the vibration detected bythe gyro 6807 p) is described. That is, a result of the comparison ofangles is described in the example illustrated in FIG. 10. Accordingly,the gain 1001 becomes roughly constant and the phase 1002 is roughly “0”in the vibration frequency band.

In the example illustrated in FIG. 10, the gain 1001 is attenuated inthe low frequency area (in the range of frequencies lower than 0.1 Hz)in the gain 1001 due to the above-described “0.1 Hz break-frequencyfirst-order HPF processing” and “0.1 Hz break-frequency first-orderintegration processing”.

As described above, in the example illustrated in FIG. 10, thecomparison target differs from that in FIGS. 6 and 7 (e.g., thevibration angular velocity and the integral value thereof are comparedwith each other in the examples illustrated in FIGS. 6 and 7 whereas inthe example illustrated in FIG. 10, the angles are mutually compared inthe example illustrated in FIG. 10). Accordingly, the waveform of theintegration processing illustrated in FIG. 10 becomes similar to thewaveform of the HPF processing, by which a frequency of 0.1 Hz or lessmay be attenuated.

In the example illustrated in FIG. 10, a high-frequency area of thewaveform 1001 (a frequency band as high as or exceeding 100 Hz) isattenuated due to a mechanical response characteristic of the vibrationcorrection unit 6806.

As described above, the vibration correction band is set by executingthe HPF processing, the integration processing, and the mechanicalresponse. Thus, the image shake in the vibration band indicated by thearrow 404 is corrected.

As described above, the image shake may not be corrected with highaccuracy when the mechanical response characteristic is high (i.e., ifthe vibration correction unit does not respond to the frequency band of10 Hz or higher) as well as when the break frequency in the integrationprocessing is close to the vibration frequency band. In this regard, inthe present exemplary embodiment, the HPF processing, the integrationoperation, and the mechanical response characteristic are executed andset at high accuracy according to the vibration band.

Returning to FIG. 3, a configuration for correcting the parallelvibration is described in detail below.

The output of the gyro 6807 p is input to the lens CPU 6808.Furthermore, the output is then input to an HPF integration filter 310.Then, the HPF integration filter 310 filters out DC components from theoutput. Furthermore, the HPF integration filter 310 executes integrationon the output to convert an angular velocity output ω into the angleoutput θ.

The integration break frequency of the HPF integration filter 310 isdifferent from that of the HPF integration filter 301 because of a causeto be described in detail below.

The output of the HPF integration filter 310 is input to a gainadjustment filter (hereinafter referred to as a “gain adjustment unit”)311. The operation and the effect of the gain adjustment unit 311 isdescribed in detail below.

The output of the gain adjustment unit 311 is corrected by an outputcorrection unit 309, which is also described in detail below.Furthermore, the output of the gain adjustment unit 311 is used as aparallel vibration correction target value and is added to theabove-described angular vibration correction target value.

Furthermore, an output of the gyro 6807 p, simultaneously to theabove-described processing, is input to an HPF phase adjustment filter(hereinafter simply referred to as an “HPF phase adjustment unit”) 304.The HPF phase adjustment unit 304 filters out DC components that overlapthe output of the gyro 6807 p. In addition, the HPF phase adjustmentunit 304 adjusts the phase of the signal. The HPF break frequency andthe phase adjustment is described in detail below.

An output of the HPF phase adjustment unit 304 is filtered out by a gyroband pass filter (BPF) unit (band pass unit) 306 for a frequencycomponent in a predetermined band.

The output of the ACC 101 p is input to an HPF integration filter 305.The HPF integration filter 305 filters out a DC component that issuperposed on the ACC 101 p. Furthermore, the HPF integration filter 305executes first-order integration on the output of the ACC 101 p toconvert the output into a velocity V. The HPF break frequency and theintegration break frequency is described in detail below.

The output of the HPF integration filter 305 is input to an ACC BPF unit(band pass filter) 307. The ACC BPF unit 307 extracts a frequencycomponent of a predetermined band only. A comparison unit 308 comparesthe outputs of the gyro BPF unit 306 and the ACC BPF unit 307 tocalculate a correction value for correcting the output of the gainadjustment unit 311.

The zoom and focus information 302 is also input to the outputcorrection unit 309. The output correction unit 309 calculates animaging magnification based on the zoom and focus information 302.Furthermore, the output correction unit 309 corrects the output of thegain adjustment unit 311 by using the calculated imaging magnificationand the above-described correction value. In addition, the outputcorrection unit 309 sets the corrected output as the parallel vibrationcorrection target value.

The calculated parallel vibration correction target value is added tothe above-described angular vibration correction target value. Then, theangular vibration correction target value added with the parallelvibration correction target value is output to the driving unit 6809. Inthe above-described manner, the vibration correction unit 6806 is drivenby the driving unit 6809 and both image shakes, namely, the angularvibration and the parallel vibration, are corrected.

With respect to the above-described configuration, at first, acorrection value output from the comparison unit 308 is described below.

FIG. 11 illustrates the angular vibration 6803 p and the parallelvibration 101 pb, which are applied to the camera. Referring to FIG. 11,parallel vibration (Y) 101 pb and angular vibration (θ) 6803 p at theprincipal point of the imaging optical system of the photographic lens6801 and a rotational radius (L) 1101 p around a rotational center (O)1102 p can satisfy the following expressions (1) and (2):

Y=Lθ  (1)

V=Lω  (2)

where the rotational radius L 1101 p denotes a distance between therotational center 1102 p and the ACC 101 p.

In the present exemplary embodiment, the expression (1) is an expressionfor calculating a rotational radius L when a displacement Y iscalculated by second-order integrating the output of the ACC 101 p, andthe output of the gyro 6807 p is first-order integrated to calculate theangle θ. The expression (2) is an expression for calculating arotational radius L when the velocity V is calculated by first-orderintegrating the output of the ACC 101 p and when an angular velocity ωis calculated based on the output of the gyro 6807 p. Both theexpressions (1) and (2) can be used to calculate the rotational radiusL.

Vibration δ, which may occur on the image plane, can be calculated bythe following expression (3):

δ=(1+β)fθ+βY   (3)

where “Y” denotes the parallel vibration at the principal point of theimaging optical system, “θ” denotes the vibration angle of the imagingoptical system, “f” denotes a focal length of the imaging opticalsystem, and “β” denotes an imaging magnification.

The symbols “f” and “β” of the first term of the right side of theexpression (3) can be calculated based on information regarding the zoomand focus of the imaging optical system, the imaging magnification β,and the focal length information f. The vibration angle θ can becalculated based on a result of integration by the gyro 6807 p.Accordingly, the angular vibration can be corrected by using theabove-described information as described above with reference to FIG. 3.

The second term of the right side of the expression (3) can becalculated based on the second-order integral value Y of the ACC 101 pand the imaging magnification β, which can be calculated by thesecond-order integral value Y of the ACC 101 p, the zoom and focusinformation 302, and the imaging magnification β, which can becalculated based on the zoom and focus information 302. Accordingly, theparallel vibration can be corrected by using the above-describedinformation as described above with reference to FIG. 3.

However, in the present exemplary embodiment, correction of image shakeis executed with respect to vibration δ, which can be acquired by thefollowing expression (4), which is a modification of the expression (3):

δ=(1+β)fθ+βLθ  (4).

More specifically, with respect to the parallel vibration, the presentexemplary embodiment does not use the displacement Y, which can becalculated directly based on a result of detection by the ACC 101 p.

In the present exemplary embodiment, image shake is corrected based onthe rotational radius L, which can be calculated according to theexpression (1) or (2), and also based on a result of integrating theoutput of the gyro 6807 p, information regarding zoom and focus, andimaging magnification β, which can be calculated based on the zoom andfocus information. With respect to the expression (4), the first term ofthe right side is an angular vibration correction target value and thesecond term of the right side is the parallel vibration correctiontarget value.

In the present exemplary embodiment, the ACC 101 p is provided at theprincipal point of the lens of the imaging optical system. Therotational radius L 1101 p is equivalent to the distance between therotational center 1102 p and the principal point of the lens of theimaging optical system.

The above-described value Y can be calculated by second-orderintegrating the output of the ACC 101 p. Accordingly, parallel vibrationcan be corrected according to the expression (3). However, for thefollowing reasons, the present exemplary embodiment uses the expression(4) to correct parallel vibration.

FIG. 12 is a block diagram illustrating an example of a signal detectionsystem of the ACC 101 p according to the present exemplary embodiment.More specifically, FIG. 12 illustrates the relationship between thevibration angle θ around the rotational center 1102 p (FIG. 11) and thedisplacement Y 101 pb, of the parallel vibration at the lens principalpoint, which may occur when the vibration angle θ is input.

When vibration of a vibration angle of θ is input to the ACC 101 p, theACC 101 p detects a variation of the component of gravity applied due tothe tilting of the camera caused by the vibration. In a range in whichthe vibration angle θ is not large, a gravitational acceleration α1 (anoutput of a circuit unit 1201) output according to the variation ofapplied gravity is proportional to the vibration angle θ.

A parallel vibration displacement Y′ (an output of a circuit unit 1202)can be acquired by multiplying the vibration angle θ by the rotationalradius L 1101 p (FIG. 11). The ACC 101 p outputs a parallel vibrationacceleration α2, which can be acquired by second-order differentiatingthe parallel vibration displacement Y′ with the circuit unit 1203.

Furthermore, the output of the ACC 101 p may include noise superposedthereupon. The noise includes noise that is constant regardless of thefrequency and noise that varies according to the frequency in actualcases. In the present exemplary embodiment, it is supposed that noise isindependent from the frequency and varies in proportion to the vibrationangle θ.

In the present exemplary embodiment, a noise-processing circuit unit1204 outputs a noise acceleration α3. The sum of the accelerations α1,α2, and α3 is output from the ACC 101 p. The output of the ACC 101 p issecond-order integrated by a circuit unit 1205. Thus, the parallelvibration displacement Y can be acquired.

The signal detection system illustrated in FIG. 12 can be expressed bythe following expression (5):

$\begin{matrix}{Y = {\left\{ {{\left( {L - \frac{G}{\omega^{2}}} \right){\sin \left( {{\omega \; t} + \varphi} \right)}} + {\frac{k}{\omega^{2}}{\sin \left( {{\omega \; t} + \varphi} \right)}}} \right\} \theta}} & (5)\end{matrix}$

where “G” denotes a gravitational acceleration-proportional item, “L”denotes the rotational radius, “k” denotes a noise-proportional term,and “ω” denotes the angular frequency.

The first term of the right side of the expression (5) includes a termof the acceleration output (a component of the acceleration α1 outputfrom the circuit unit 1201) and the gravitational acceleration output (acomponent of the acceleration α2 output from the circuit unit 1202). Thesecond term of the right side of the expression (5) includes a term ofnoise (a component of the acceleration α3 output from the circuit unit1204).

In the present exemplary embodiment, both the acceleration output andthe gravitational acceleration output are related to the phase of thevibration angle θ while the noise is not. Accordingly, the right side ofthe expression (5) includes two independent terms. If the phase of eachof the two terms is ignored for simple description, the followingexpressions (6) and (7) can hold:

$\begin{matrix}{Y = {\left( {L - \frac{G - k}{\omega^{2}}} \right)\sin \; \omega \; t}} & (6) \\{L = {\frac{G - k}{\omega^{2}}.}} & (7)\end{matrix}$

More specifically, with respect to the displacement of the parallelvibration, the gravitational acceleration and the noise dominantlyaffect in the low-frequency band at each frequency at which the equationof the expression (7) holds (each frequency at which a result of theexpression (6) is “0”). Accordingly, the displacement of the parallelvibration can be detected with high accuracy in only the high-frequencyband.

FIG. 13 is a Bode diagram of a case when values of rotational radius Land the like are applied to the expression (6) according to actualresults of vibration detection. Referring to FIG. 13, a frequency isshown on the horizontal axis while a gain of parallel vibrationdisplacement Y relative to the input vibration angle θ, which isdetected by the ACC 101 p, is shown on the vertical axis. The scalingunit of scaling the gain is “power”.

If the scale of the gain is the power at one instant, it is indicatedthat the parallel vibration Y is accurately calculated with respect tothe input vibration angle θ. In the example illustrated in FIG. 13, thedetection has been started at a very low level of gain 1301 of 1.3 Hzbecause the parallel vibration acceleration detected by the ACC 101 p isset off by the gravitational acceleration and the noise.

Furthermore, in the example illustrated in FIG. 13, in a frequency bandbelow 1.3 Hz, the output of the ACC 101 p increases as the frequencybecomes lower because the gravitational acceleration and noise dominatesin the frequency band below 1.3 Hz. On the other hand, as indicated byan arrow 1302, the accuracy of the output detected by the ACC 101 p ishigh above 1.3 Hz.

As is indicated by the arrow 404 in the example illustrated in FIG. 13,the band of vibration ranges from 1 to 10 Hz, in which the gravitationalacceleration and the noise affect. Accordingly, the parallel vibrationis not detected with the ACC 101 p. In this regard, in order to detectthe parallel vibration by using the band (indicated by an arrow 1302) ofaccurate frequency of the ACC 101 p, the present exemplary embodimentuses the expression (4) instead of the expression (3).

More specifically, the present exemplary embodiment calculates therotational radius L by comparing the acceleration output first-orderintegral value and the angular velocity output or by comparing theacceleration output second-order integral value and the angular velocityoutput first-order integral value. Furthermore, the present exemplaryembodiment uses the expression for calculating a parallel vibrationcomponent based on the calculated rotational radius L and the angularvelocity output.

The present exemplary embodiment compares the output of the ACC 101 pand the output of the gyro 6807 p (divides the acceleration output bythe angular velocity output) to calculate the rotational radius L. Inthis regard, the present exemplary embodiment suppresses or reduces theabove-described influence from the gravitational acceleration and thenoise by extracting and comparing the acceleration output and theangular velocity output in only the band indicated by the arrow 1302(FIG. 13).

In the present exemplary embodiment, both the gyro BPF unit 306 and theACC BPF unit 307 illustrated in FIG. 3 are the same band pass filters(BPFs) that extract the output in the band of 5 Hz only. FIG. 14illustrates characteristics of the gyro BPF unit 306 and the ACC BPFunit 307.

In the example illustrated in FIG. 14, the frequency is shown on thehorizontal axis. On the vertical axis, a gain 1401 representing anoutput ratio of the output of HPF phase adjustment unit 304 or HPFintegration filter 305 to the output of the gyro BPF unit 306 or the ACCBPF unit 307, and a phase 1402 are shown. Note that the unit of the gain1401 is db.

With respect to the filter characteristic, a 5 Hz signal passes throughthe filter but a 0.5 Hz signal or a 50 Hz signal is attenuated. Morespecifically, the 5 Hz signal passes through the filter and is outputfrom the filter unmodified because the gain of the 5 Hz signal is 0 db.On the other hand, the 0.5 Hz signal or the 50 Hz signal is attenuatedby the filter to one tenth because the gain of the 0.5 Hz signal or the50 Hz signal is −20 db.

It is also useful if a higher-order filter is used to more efficientlyspecify the frequency to be extracted. More specifically, it is alsouseful if a second-order BPF filter is provided having a characteristicin which a 5 Hz signal passes through the filter (the input signal isoutput from the filter unmodified because the gain of the 5 Hz signal is0 db) but a 0.5 Hz or 50 Hz signal is attenuated by the filter(attenuated to one hundredth as the gain of the signal is −40 db), asindicated with a gain 1501 in FIG. 15.

With respect to the phase 1502, in the case of the 5 Hz signal, thephase of the output in relation to the input signal is “0” but maygreatly vary across the frequency of 5 Hz. However, the variation in thephase would not cause a problem if the variation of the phases of theoutputs from the gyro BPF unit 306 and the ACC BPF unit 307 are thesame, because it is intended merely to compare the outputs of the gyroBPF unit 306 and the ACC BPF unit 307.

With regard to the break frequency of the HPF phase adjustment unit 304and the HPF integration filter 305, it is not necessary to use the samebreak frequency as that of the HPF integration filter 301 in ordermerely to compare the angular velocity output and the velocity output.Accordingly, it is useful if the HPF break frequency is set at a highfrequency of 1 Hz, for example, to increase the capacity to filter outDC components. In addition, it is also useful if the velocity output.Accordingly, it is useful if the integration break frequency is set at ahigh frequency of 1 Hz, for example.

In general, in executing HPF processing and integration, the time takento achieve a stable state becomes longer if the break frequency becomeslower. In this regard, the time taken to achieve a stable state can bereduced by setting the break frequency to a high frequency. In thiscase, to improve the comparison accuracy, it is also useful if thevariation in the phase occurring in the HPF phase adjustment unit 304and that occurring in the HPF integration filter 305 are the same.

FIG. 16 is a Bode diagram illustrating an example of a characteristic ofthe HPF integration filter 305. The DC components of the output of theACC 101 p (hereinafter may also be simply referred to as an “ACCoutput”) is filtered out by the HPF processing. Then, the output issubjected to integration. Then, the integrated output is converted intovelocity. In the example illustrated in FIG. 16, the frequency is shownon the horizontal axis. The gain of the ratio of the output of the HPFintegration filter 305 to the acceleration output is shown on thevertical axis in units of db.

Referring to FIG. 16, with respect to a gain 1601, a low frequency of 1Hz or lower is attenuated and a high frequency higher than 1 Hz isintegrated (the gain is reduced in proportional to the frequency) as itscharacteristic. Now, to direct attention to and particularly describeonly the case of a frequency of 5 Hz, which is to be extracted by theACC BPF unit 307, a phase 1602 leads 23 degrees with respect to thephase of −90 degrees, which is an ideal phase after integration, asindicated by an arrow 1603. Accordingly, it may be useful for comparisonif the same lead (i.e., 23 degrees) occurs at the frequency of 5 Hz withrespect to the HPF phase adjustment unit 304.

FIG. 17 is a Bode diagram illustrating an exemplary characteristic ofthe HPF phase adjustment unit 304 according to the present exemplaryembodiment. The DC components of the output of the gyro 6807 p(hereinafter may also be simply referred to as a “gyro output”) arefiltered out by the HPF processing.

In the example illustrated in FIG. 17, the frequency is shown on thehorizontal axis. The gain of the ratio of the output of the HPF phaseadjustment unit 304 to the gyro output is shown on the vertical axis inunits of db.

Referring to FIG. 17, with respect to a gain 1701, a low frequency aslow as 1 Hz or lower is attenuated as the characteristic. Now, to directattention to and particularly describe only the case of the frequency of5 Hz, which is to be extracted by the gyro BPF unit 306, a phase 1702leads 23 degrees with respect to the phase of 0 degrees (an ideal phaseafter integration), as indicated by an arrow 1703, which is the same asthe variation of phase occurring in the HPF integration filter 305. Thisis because a second-order HPF additionally including the above-describedHPF is used as a phase adjustment unit in the present exemplaryembodiment.

Suppose here that the phase adjustment unit is omitted and a first-orderHPF similar to the HPF by the HPF integration filter 305 is used. Inthis case, as illustrated in FIG. 18, even a variation of the gain 1801at 5 Hz is small, but a phase 1802 of 5 Hz leads by 11 degrees, asindicated by an arrow 1803 in FIG. 18. That is, the displacement of theHPF integration filter 305 is not 23 degrees.

Accordingly, the present exemplary embodiment uses the additionallyprovided HPF unit as the phase adjustment unit to adjust thedisplacement of the phase of the acceleration output in the HPFintegration filter 305 and the phase of the angular velocity output inthe HPF phase adjustment unit 304 to the same level.

As described above, the present exemplary embodiment compares theoutputs of the gyro 6807 p and the ACC 101 p in the frequency bandillustrated in FIGS. 14 and 15 (hereinafter also referred to as a “firstfrequency band”), which is narrower than the frequency band illustratedin FIG. 10 (hereinafter also referred to as a “second frequency band”).With the above-described configuration, the present exemplary embodimentcan execute the comparison of the acceleration output and the angularvelocity output after attenuating the gravitational components and noisesuperposed on the acceleration output with high accuracy.

Returning to FIG. 3, the comparison unit 308 calculates the rotationalradius L by the following expression (8) by comparing the output ω ofthe gyro BPF unit 306 and the output V of the ACC BPF unit 307:

L=V/ω  (8).

Furthermore, by using the calculated rotational radius L, the presentexemplary embodiment corrects image shake according to theabove-described expression (4). Moreover, the present exemplaryembodiment multiplies the rotational radius L calculated by thecomparison unit 308 by the output of the gain adjustment unit 311. Then,the output correction unit 309 sets the resulting value as the parallelvibration correction target value.

In light of expression (4), which includes terms such as the rotationalradius L, the vibration angle output (the vibration angle θ), and theimaging magnification β (the imaging magnification β can be calculatedbased on the zoom and focus information 302), it may seem useful if theoutput of the HPF integration filter 301 is directly multiplied by therotational radius L (a correction value) as illustrated in FIG. 19.

However, for the following reasons, the present exemplary embodimentdoes not use the output of the HPF integration filter 301 as thecorrection value, but includes the HPF integration filter 310 and thegain adjustment unit 311 as dedicated parallel vibration correctionunits as illustrated in FIG. 3.

The function of the gain adjustment unit 311 illustrated in FIG. 3 isdescribed in detail below. As described above, the rotational radius Lcan be calculated by using the expression (8). However, strictlyspeaking, the rotational radius L can differ with respect to eachfrequency to be extracted.

FIG. 20 illustrates exemplary variation of the rotational radius L whenthe frequency to be extracted by the gyro BPF unit 306 and the ACC BPFunit 307 illustrated in FIG. 3 in the range of 1 to 10 Hz.

In the example illustrated in FIG. 20, the frequency is shown on thehorizontal axis. The ratio of the rotational radius L of each frequencyto the rotational radius L at the frequency of 5 Hz is shown on thevertical axis in units of db.

Referring to FIG. 20, variation of rotational radius L 2001 decreases inproportion to the frequency. The decrease of the rotational radius L2001 specifically indicates that the high-frequency vibration hasoccurred around a point of contact between the camera and thephotographer (the face of the photographer, for example). The lower thefrequency becomes, the more distant from the camera the rotationalradius L becomes (from the face to the elbow of the photographer, forexample). Accordingly, it is necessary to calculate a differentrotational radius L for each frequency.

However, it is not possible to provide a plurality of correction valuesthat the output correction unit 309 can use to scale the angularvelocity integral output (vibration angle θ). Accordingly, the gainadjustment unit 311 provides different characteristics to the angularvelocity integral output of the HPF integration filter 310 (thevibration angle θ). Thus, the present exemplary embodiment can acquirean optimum parallel vibration correction target value for each frequencyeven when multiplication by a specific correction value is executed.Thus, the gain adjustment unit 311 adjusts the variation of therotational radius L, which is used as a correction value in themultiplication, by adjusting the characteristic of the integral outputfrom the gyro 6807 p, which is the target of multiplying the correctionvalue.

FIG. 21 is a Bode diagram illustrating an example of operation of thegain adjustment unit 311 according to the present exemplary embodiment.In the example illustrated in FIG. 21, the frequency is shown on thehorizontal axis. The ratio of the output of the gain adjustment unit 311to the output of the HPF integration filter 310 is shown on the verticalaxis in units of db. The phase of the output is also shown on thevertical axis.

In the example illustrated in FIG. 21, the higher the frequency of again 2101 becomes, the more the output is attenuated in substantialproportion to the rise of the frequency. In this regard, for example,when the output correction unit 309 multiplies the output of the gainadjustment unit 311 by the rotational radius L as a specific correctionvalue in the case of extraction at the frequency of 5 Hz, a result canbe acquired which is similar to that in the case of multiplying theoutput of the HPF integration filter 310 by the different rotationalradiuses L (FIG. 20) for each frequency.

However, in the example illustrated in FIG. 21, a phase 2102 is greatlydisplaced in the vibration band 404. In this regard, at the frequency of1 Hz, the phase is delayed by 18 degrees. In this regard, in the presentexemplary embodiment, to set off the delay of the phase, thecharacteristic of the HPF integration filter 310 is different from thecharacteristic of the HPF integration filter 301 in order.

As described above, the break frequency of the HPF integration filter301 is set to a frequency of 0.1 Hz for both HPF and integration. Thus,the present exemplary embodiment reduces the phase displacement at thevibration lower limit frequency of 1 Hz to be small. On the other hand,in the present exemplary embodiment, the integration break frequency ofthe HPF integration filter 310 is set to 0.5 Hz.

FIG. 22 is a Bode diagram illustrating operation of the HPF integrationfilter 310 according to the present exemplary embodiment. In the exampleillustrated in FIG. 22, the frequency is shown on the horizontal axis.The ratio of the output of the HPF integration filter 310 to the outputof the gyro is shown on the vertical axis in units of db. The phase ofthe output is also shown on the vertical axis.

Referring to FIG. 22, a gain 2201 has a sufficient integrationcharacteristic in the vibration band 404. For example, in the vibrationband 404, the output decreases in proportion to the frequency. However,the phase delay of a phase 2202 is short by 34 degrees at the vibrationlower limit frequency as indicated by an arrow 2203. More specifically,a phase delay of only 56 degrees has actually occurred while a phasedelay of 90 degrees is required.

However, with respect to the signal from the gyro that has passedthrough both the HPF integration filter 310 and the gain adjustment unit311, the phase delay after the gain adjustment can set off the shortagein the phase delay in the HPF integration filter 310.

FIG. 23 is a Bode diagram illustrating an exemplary characteristic of asignal output from the gyro having passed through both the HPFintegration filter 310 and the gain adjustment unit 311 according to thepresent exemplary embodiment. In the example illustrated in FIG. 23, thefrequency is shown on the horizontal axis. The ratio of the output ofthe HPF integration filter 310 to the gyro output is shown on thevertical axis in units of db. The phase of the output is also shown onthe vertical axis.

Referring to FIG. 23, with respect to a gain 2301, a sufficientintegration characteristic (e.g., the output reduces in proportion tothe frequency) and a characteristic for correcting the dependency of therotational radius on the frequency are acquired in the vibration band404. With respect to a phase 2302, a relatively small phase shortage ofonly 16 degrees has occurred at the vibration lower limit frequency inthe vibration band 404 as indicated by an arrow 2303.

As described above, if the output correction unit 309 multiplies theoutput of the gain adjustment unit 311 by the rotational radius L at afrequency of 5 Hz as a specific correction value, then a result can beacquired that is roughly similar to the result of multiplying the outputof the HPF integration filter 310 by different rotational radiuses L(FIG. 20) for each frequency.

As described above with reference to FIG. 3, the present exemplaryembodiment includes the gyro BPF unit 306 and the ACC BPF unit 307.Furthermore, the present exemplary embodiment compares the outputs ofthe gyro 6807 p and the ACC 101 p in the frequency band illustrated inFIGS. 14 and 15 (the first frequency band), which is narrower than thefrequency band illustrated in FIG. 10 (the second frequency band).Accordingly, the present exemplary embodiment can execute the comparisonof the acceleration output and the angular velocity output afterattenuating the gravitational components and noise superposed on theacceleration output with high accuracy.

Furthermore, the present exemplary embodiment calculates an angularvibration correction target value and a parallel vibration correctiontarget value according to the output of the gyro 6807 p. In this regard,as illustrated in FIG. 3, the present exemplary embodiment calculatesthe angular vibration correction target value with the HPF integrationfilter 301 and the parallel vibration correction target value with theHPF integration filter 310.

More specifically, the frequency band of the angular vibration and thatof the parallel vibration differ from each other in the presentexemplary embodiment. Furthermore, the present exemplary embodiment setsa frequency characteristic different from that used in the calculationfor the angular vibration correction target value by using the gainadjustment unit 311.

With the above-described configuration, the present exemplary embodimentcan correct each of the angular vibration and the parallel vibrationwith high accuracy. The above-described method for extracting theangular velocity output and the acceleration output in the narrowfrequency band (the first frequency band) is not limited to the BPFprocessing.

FIG. 24 illustrates another exemplary configuration of the imagestabilization control apparatus according to the present embodimentconfigured to calculate a spectrum of the gyro 6807 p and the ACC 101 pat a frequency at which the comparison is desired to be executed withthe publicly known Fourier transform and configured to compare theresults with the comparison unit 308.

Referring to FIG. 24, a gyro Fourier transform unit 2401 and an ACCFourier transform unit 2402 each calculate a spectrum by multiplying thegyro output and the ACC output by a frequency component to be extractedand integrating the multiplication result.

The spectrum of the ACC 101 p can be expressed by the followingexpression (9) while that of the gyro can be expressed by the followingexpression (10). Note here that with respect to the description of thephase to be described further below, the expressions (9) and (10) willnot be expressed using a complex sinusoidal wave.

$\begin{matrix}{V_{F} = \sqrt{\left( {\sum\limits_{i = 0}^{\frac{n}{f}}\; {{G(t)}\sin \; 2\pi \; {ft}}} \right)^{2} + \left( {\sum\limits_{i = 0}^{\frac{n}{f}}\; {{G(t)}\cos \; 2\pi \; {ft}}} \right)^{2}}} & (9) \\{\omega_{F} = \sqrt{\left( {\sum\limits_{i = 0}^{\frac{n}{f}}\; {{H(t)}\sin \; 2\pi \; {ft}}} \right)^{2} + \left( {\sum\limits_{i = 0}^{\frac{n}{f}}\; {{H(t)}\cos \; 2\pi \; {ft}}} \right)^{2}}} & (10)\end{matrix}$

In the expressions (9) and (10), “f” denotes a frequency to be extracted(e.g., f=5 Hz), “n” denotes an integer (e.g., n=1), “G(t)” denotes anoutput at each sampling timing of the velocity at the frequency to beextracted, and “H(t)” denotes an output at each sampling timing of theangular velocity at the frequency to be extracted.

The expressions (9) and (10) respectively express the synthesis of thedefinite integral value of the sine wave and the cosine wave of aperiodic integral multiple of the frequency to be extracted. Aftercalculating the velocity and the angular velocity by using a result of acalculation using the expressions (9) and (10), the rotational radius Lcan be calculated using the expression (8).

In the example illustrated in FIG. 3, the magnitude of the velocity ofthe frequency component to be extracted is calculated using the BPF thatpasses the frequency component of the integral output of the ACC 101 p(velocity). Furthermore, the magnitude of the velocity of the frequencycomponent to be extracted is calculated using the BPF that passes thefrequency component of the output of the gyro 6807 p. Moreover, therotational radius L is calculated by comparing the resulting magnitudesof the frequency components.

In the example illustrated in FIG. 24, the present exemplary embodimentcalculates the spectrum of the frequency component to be extracted ofthe integral outputs of the ACC 101 p (the velocity) by Fouriertransform. Similarly, the present exemplary embodiment calculates thespectrum of the frequency component of the outputs of the gyro 6807 p byFourier transform. Furthermore, the present exemplary embodimentcompares the spectra to calculate the rotational radius L.

In the present exemplary embodiment, instead of the HPF phase adjustmentunit 304 and the HPF integration filter 305 illustrated in FIG. 24, HPFintegration phase adjustment units 2501 and 2601 and HPF second-orderintegration filters 2502 and 2602 are provided as illustrated in FIGS.25 and 26.

It is also useful if the rotational radius L is calculated using thefollowing expression (11) including terms such as an angle θ, which isan integral of the output ω of the gyro 6807 p, and a displacement Y,which is calculated by second-order integrating the output a of the ACC101 p.

L=Y/θ  (11)

In the above-described manner, the influence from the noise of thehigh-frequency component can be reduced by integrating the angularvelocity output and second-order integrating the acceleration.Accordingly, the present exemplary embodiment can constantly andsecurely calculate the rotational radius L.

A method for actually calculating the rotational radius L, which is theresult of applying the expression (8) or the expression (11), isdescribed in detail below. In the method that uses the expression (11),in which the angle θ and the displacement Y are compared to calculate Y,processing is executed which is similar to that in the case of using theexpression (8). Accordingly, the description of the method using theexpression (11) will be omitted and the method using the expression (8),in which the angular velocity ω and the velocity V are compared tocalculate the rotational radius L, will be described.

When the BPF is used, an output waveform 2701 of the HPF phaseadjustment unit 304 and an output waveform 2702 of the HPF integrationfilter 305 are sampled at intervals of a predetermined time period asillustrated in FIG. 27. The result of sampling the output waveform 2701is set as an angular velocity ω1 while that of the output waveform 2702is set as a velocity V1. In the example illustrated in FIG. 27, time isshown on the horizontal axis while the angular velocity and theacceleration after BPF are shown on the vertical axis.

Referring to FIG. 27, arrows 2703 through 2709 indicate samplingperiods. Arrows 2710 (ω1), 2711 (ω2), 2712 (ω3), 2713 (ω4), 2714 (ω5),2715 (ω6) 2716 (ω7) each indicate the difference ωn between the angularvelocities in the above-described sampling periods. Arrows 2717 (V1),2718 (V2), 2719 (V3), 2720 (V4), 2721 (V5), 2722 (V6), and 2723 (V7)each indicate the difference Vn between the velocities in theabove-described sampling periods.

As the sampling period, a half of the period of the extracted frequencyis set. In this regard, for example, if the frequency of 5 Hz isextracted, the sampling period of 0.1 second is set.

In the present exemplary embodiment, a rotational radius L1 iscalculated based on the angular velocity difference ω1 and the velocitydifference V1 calculated in the period 2703 using the expression (8).Similarly, a rotational radius L2 is calculated based on the angularvelocity difference ω2 and the velocity difference V2 using theexpression (8) from a subsequent sample.

By serially calculating rotational radiuses L and averaging thecalculated rotational radiuses L in the above-described manner, a stablerotational radius L is calculated. The average value is calculated bythe following expression (12):

$\begin{matrix}{L = \frac{\sum\limits_{i = 1}^{n}\; L_{1}}{n}} & (12)\end{matrix}$

where “n” denotes the number of times of sampling operations.

The present exemplary embodiment uses the rotational radius L calculatedin the above-described manner and further calculates the amount ofvibration occurring on the image plane using the above-describedexpression (4) to correct image shake. More specifically, the presentexemplary embodiment outputs the rotational radius L calculated usingthe expression (12) to the output correction unit 309 (FIG. 3) as acorrection value.

In the present exemplary embodiment, instead of correcting image shakeoccurring at a specific moment by calculating the amount of vibration onthe image plane at a specific moment by using both a rotational radiusLi (e.g., the rotational radius L1) in each sampling period and theexpression (4), an average value of the rotational radiuses L calculatedfor the sampling periods is calculated and the amount of vibrationoccurring on the image plane is calculated based on the calculatedaverage value by using the expression (4). In this regard, the reasonfor employing this configuration is as follows.

An angular velocity output and an acceleration output naturally includesa large amount of noise components. Accordingly, the reliability of therotational radius L calculated for one period only is low. In thisregard, the present exemplary embodiment uses an average value of therotational radiuses L to calculate a stable rotational radius L.

As described above, the present exemplary embodiment calculates therotational radius L based on the result of the sampling in each period.However, the present exemplary embodiment is not limited to this. Forexample, a method that utilizes a peak of a waveform or a method thatutilizes the area of a waveform can be used.

FIG. 28 illustrates an example of the method that utilizes a peak of awaveform. In the example illustrated in FIG. 28, the time is shown onthe horizontal axis while the angular velocity and the accelerationafter BPF are shown on the vertical axis.

Referring to FIG. 28, arrows 2801, 2802, and 2803 are sampling periods.Arrows 2804 (ω1), 2805 (ω2), and 2806 (ω3) each indicate an angularvelocity difference ωn between a maximum value and a minimum valueduring the sampling period. Arrows 2807 (V1), 2808 (V2), and 2809 (V3)each indicate a velocity difference Vn during the sampling period.

As the sampling period, one period of the extracted frequency is set. Inthis regard, for example, if a frequency of 5 Hz is extracted, asampling period of 0.2 seconds is set.

In the present exemplary embodiment, a rotational radius L1 iscalculated based on the angular velocity difference ω1 and the velocitydifference V1 calculated in the period 2801 as well as by using theexpression (8). Similarly, a rotational radius L2 is calculated based onthe angular velocity difference ω2 and the velocity difference V2 and byusing the expression (8) from a subsequent sample.

By serially calculating rotational radiuses L and averaging thecalculated rotational radiuses L in the above-described manner, a stablerotational radius L is calculated using the following expression (12).

FIG. 29 illustrates an example of the method that utilizes the area of awaveform. In the example illustrated in FIG. 29, time is shown on thehorizontal axis while the angular velocity after BPF and the velocitycalculated by integrating the acceleration are shown on the verticalaxis.

Referring to FIG. 29, a waveform 2901 indicates a waveform of anabsolute value of the angular velocity output (the output of the HPFphase adjustment unit 304). A waveform 2902 indicates a waveform of anabsolute value of the velocity output (the output of the HPF integrationfilter 305).

An arrow 2903 indicates a sampling period, which is a time period frompressing of a main power switch of the camera to the start of capture,for example. The sampling period can also be a time period from thehalf-press of the release button 6804 a of the camera to the start ofcapture or from a timing at which the orientation of the camera hasbecome stable to the completion of focus on an object or to a timing atwhich an object distance is detected. The present exemplary embodimentcalculates an area 2904 of the waveform 2901 and an area 2905 of thewaveform 2902 during the sampling period 2903, which are indicated withdashed lines.

The area 2904 (Sω) and the area 2905 (Sv) can satisfy the followingconditions (13) and (14):

$\begin{matrix}{S_{\omega} = {\sum\limits_{i = 0}^{T}\; {t{\omega_{t}}}}} & (13) \\{S_{V} = {\sum\limits_{i = 0}^{T}\; {t{V_{t}}}}} & (14)\end{matrix}$

where “T” denotes the sampling period 2903.

Accordingly, the rotational radius L can be calculated by the followingexpression (15) for calculating an average value of the rotationalradiuses L:

$\begin{matrix}{L = {\frac{S_{V}}{S_{\omega}} = {\frac{\sum\limits_{t = 0}^{T}\; {V_{t}}}{\sum\limits_{t = 0}^{T}\; {\omega_{t}}}.}}} & (15)\end{matrix}$

As described above, by using the area during a sampling period, a stablerotational radius L can be calculated that is not affected by noise ormomentary disturbance.

A method is described in detail below for calculating a rotationalradius L based on a result of calculating the spectrum by executingFourier transform, as illustrated in FIG. 24, instead of executing theBPF.

In this method, at first, a spectrum VF of the velocity calculated byintegrating the acceleration output and a spectrum ωF are calculatedusing the expressions (9) and (10). Then, a rotational radius LF iscalculated using the following expression (16):

$\begin{matrix}{{LF} = {\frac{VF}{\omega \; F}.}} & (16)\end{matrix}$

In this case, “n” in the expressions (9) and (10) is substituted with“f” and the value of “f” is set as one period of the frequency to beextracted. More specifically, the present exemplary embodimentcalculates the rotational radius LF based on the spectra VF and ωF foreach of the sampling periods 2801, 2802, and 2803 illustrated in FIG.28. Furthermore, the present exemplary embodiment averages therotational radiuses LF calculated for each period and outputs theresulting average value to the output correction unit 309 (FIG. 24) as acorrection value.

Alternatively, it is also useful if the spectra VF and ωF during thesampling period 2903 (FIG. 29),are calculated using the expressions (9)and (10). In this case, the present exemplary embodiment can calculatethe rotational radius LF using the expression (16) based on the resultof calculating the spectra. Furthermore, in this case, although thepresent exemplary embodiment does not average the rotational radiusesLF, the spectra VF and ωF are averaged as a result of a long time periodtaken for calculating the spectra VF and ωF. Thus, the present exemplaryembodiment can calculate a stable rotational radius L.

FIG. 30 is a timing chart illustrating processing for correcting theabove-described angular vibration and parallel vibration according tothe present exemplary embodiment. In the example illustrated in FIG. 30,time is shown on the horizontal axis. The upper portion of each verticalaxis indicates a high (Hi) state while the lower portion thereofindicates a low (Lo) state.

Referring to FIG. 30, a state 3001 indicates the state of a main powerswitch of the camera 6804 (the state of main power). The “Hi” stateindicates that the main power switch is on while the “Lo” stateindicates an “off” state. A state 3002 indicates the state of a switchS1, which is set “on” by half-press of the release button 6804 a. “Hi”indicates that the switch S2 is set “on” (half-pressed state) while “Lo”indicates an “off” state (half-press-released state). A state 3003indicates the state of a switch S2, which is set “on” by fully pressingthe release button 6804 a. “Hi” indicates that the switch S2 is set “on”(fully pressed state) while “Lo” (half-pressed state) indicates an “off”state.

An operation 3004 indicates an operation for driving a quick-returnmirror, a shutter, or a diaphragm. More specifically, the operation 3004indicates an operation for securing a capture optical path that isoptimal for storing object information on the image sensor 6805. “Hi”indicates an “in operation” state. “Lo” indicates an operationsuspension state.

A state 3005 indicates a state of an exposure operation for storingobject information on the image sensor 6805. “Hi” indicates an “inoperation” state. “Lo” indicates resetting of the storage of objectinformation. In an actual operation, an operation is executed, inaddition to the exposure operation, for storing object information onthe image sensor 6805 and displaying an image of the object on a monitorprovided on a camera body back surface. However, this operation is notillustrated in FIG. 30 because it is not essential to the presentinvention.

A state 3006 indicates a state of a focus detection operation fordetecting the state of focusing of a light flux of the object that haspassed through the imaging optical system of the lens 6801 with anauto-focus (AF) sensor (not illustrated). “Hi” indicates a “focusdetection in operation” state. “Lo” indicates a “focus detectionnon-operating” state.

A state 3007 indicates the state of an operation for driving an AF lens,which is configured to adjust the focusing state by moving a part of orall lens units of the imaging optical system of the exchangeable lens6801 towards the object side after receiving a signal from the AF sensor(not illustrated). “Hi” indicates a “lens adjustment in operation”state. “Lo” indicates a “lens adjustment non-operating” state.

A state 3008 indicates a state of an operation for detecting the gyro6807 p and the ACC 101 p. “Hi” indicates a “gyro (or ACC) detection inoperation” state. “Lo” indicates a “gyro (or ACC) detectionnon-operating” state.

A state 3009 indicates a state of a rotational radius detectionoperation for detecting the rotational radius L based on the angularvelocity output and the acceleration output. “Hi” indicates a“calculation in operation” state. “Lo” indicates a “calculationnon-operating” state.

A state 3010 indicates a state of an angular vibration correctionoperation for correcting the angular vibration with the vibrationcorrection unit 6806. “Hi” indicates an “angular vibration correction inoperation” state. “Lo” indicates an “angular vibration correctionnon-operating” state.

A state 3011 indicates a state of a parallel vibration correctionoperation for correcting the parallel vibration with the vibrationcorrection unit 6806. “Hi” indicates a “parallel vibration correction inoperation” state. “Lo” indicates a “parallel vibration correctionnon-operating” state.

The above operation of each components of the camera 6804 executed whenthe main power switch is pressed at time t1 is described in detail belowwith reference to the timing chart of FIG. 30.

Referring to FIG. 30, at time t2, the photographer half-presses therelease button 6804 a (switch S1 is in an “on” state) (the state 3002shifts from the “Lo” state to the “Hi” state). In synchronization withthe half-press of the release button 6804 a, the AF sensor (notillustrated) starts detecting the focusing state (the state 3006 shiftsfrom the “Lo” state to the “Hi” state). In addition, the gyro 6807 p andthe ACC 101 p start their operation (the state 3008 shifts from the “Lo”state to the “Hi” state).

If the photographer has half-pressed the release button 6804 a, thecamera is in a stable state for capture of the object (in a state inwhich no great vibration is applied on the camera). Accordingly, in thisstate, the present exemplary embodiment can execute a stable calculationfor the ACC 101 p and the gyro 6807 p.

In this state, the calculation of a rotational radius L is started basedon the outputs of the ACC 101 p and the gyro 6807 p (the state 3009shifts from the “Lo” state to the “Hi” state). In addition, thecorrection of the angular vibration starts (the state 3010 shifts fromthe “Lo” state to the “Hi” state).

At time t3, after the state of focusing of the imaging optical system iscalculated based on the signal from the AF sensor (not illustrated),then the focusing state is adjusted by moving a part of or all of theimaging optical system towards the object side (the state 3007 shiftsfrom the “Lo” state to the “Hi” state). At the same time, thecalculation of the rotational radius L is suspended (the state 3009shifts from the “Hi” state to the “Lo” state) because the vibrationcannot be accurately detected at that time due to vibration applied tothe ACC 101 p caused by driving of the imaging optical system.

The calculation of the rotational radius L is suspended at the time t3for the following reasons.

As described above with reference to FIG. 3, the present exemplaryembodiment extracts a specific frequency (e.g., 5 Hz) only with respectto the output of the ACC 101 p. Accordingly, although theabove-described driving noise is typically attenuated to a non-affectinglevel, the output of the ACC 101 p may in actual cases become if thereis excessive, for example, vibration from the driving of the lens underadverse operating conditions.

If the acceleration output is saturated, the vibration cannot bedetected in all frequency bands. In this case, the ACC 101 p outputs anerror signal only. If the rotational radius L is calculated by using theerror signal, the parallel vibration may be inappropriately andinsufficiently corrected.

In order to prevent this, the present exemplary embodiment suspends thecalculation of the rotational radius L during the lens (focus lens)driving operation for focusing.

The saturation that may occur due to vibration from the driving of thelens may be suppressed by using an ACC having a wide accelerationdetection range (an ACC capable of detecting a very high acceleration).However, such an ACC having a wide detection range also has a lowaccuracy for detection of microacceleration such as vibration.Accordingly, if an ACC of this type is used, a stable rotational radiuscannot be detected.

In this regard, the present exemplary embodiment uses an ACC having ahigh vibration detection accuracy although the acceleration detectionrange of the ACC is relatively narrow. Accordingly, the presentexemplary embodiment prevents the use of an ACC signal that is outputwhen vibration from disturbance is input for calculating the rotationalradius.

At time t4, the lens reaches a target position and the driving of thelens is stopped (the state 3007 shifts from the “Hi” state to the “Lo”state). In synchronization with the suspension of the driving of thelens, the AF sensor (not illustrated) detects the focusing state againto determine whether a desired focusing state has been achieved (thestate 3006 shifts from the “Lo” state to the “Hi” state).

At time t5, since it has been determined that the desired focusing stateof the AF has been achieved, the detection of focusing state ends (thestate 3006 shifts from the “Hi” state to the “Lo” state). On the otherhand, if it is determined that the desired focusing state has not beenachieved, the lens is driven again to repeatedly adjust the focusingstate until the desired focusing state is achieved.

In addition, if it is determined that the desired focusing state hasbeen achieved, the operation for calculating the rotational radius isresumed (the state 3006 shifts from the “Lo” state to the “Hi” state)because there is no possibility of disturbance vibration occurring dueto the driving of the lens applied on the ACC at and after the time t5.

When the driving of the lens is stopped at time t5, the presentexemplary embodiment calculates the object distance based on the amountof driving of the lens unit. Furthermore, the present exemplaryembodiment calculates the imaging magnification based on the zoominformation and uses the calculated imaging magnification in setting theparallel vibration correction target value.

At time t6, when the photographer fully presses the release button 6804a, the switch S2 is in an “on” state (the state 3003 shifts from the“Lo” state to the “Hi” state). In synchronization with the full press ofthe release button 6804 a, the present exemplary embodiment causes thediaphragm of the exchangeable lens 6801 to operate, executes a mirror-upoperation of a quick return mirror of the camera 6804, and opens theshutter (the state 3004 shifts from the “Lo” state to the “Hi” state).

In addition, the present exemplary embodiment stops the calculation ofthe rotational radius L (the state 3009 shifts from the “Hi” state tothe “Lo” state) in order to prevent degradation of the accuracy ofcalculating the rotational radius L due to the saturation of the ACC 101p because of the vibration occurring due to the operation such as thereduction of the aperture of the diaphragm, the mirror-up operation ofthe quick return mirror, or opening the shutter.

At time t7, the present exemplary embodiment starts an exposureoperation (the state 3005 shifts from the “Lo” state to the “Hi” state).In synchronization with the start of the exposure operation, thecorrection of the parallel vibration is started (the state 3011 shiftsfrom the “Lo” state to the “Hi” state).

The present exemplary embodiment uses an average of the average valuesof the rotational radiuses L, which are calculated during the timeperiod from the time t2 to the time t3, and the average values of therotational radiuses L, which are calculated during the time period fromthe time t5 to the time t6 as the rotational radius L in correcting theparallel vibration.

At time t8, the exposure ends (the state 3005 shifts from the “Hi” stateto the “Lo” state). Furthermore, the correction of the parallelvibration also ends (the state 3011 shifts from the “Hi” state to the“Lo” state).

As described above, the present exemplary embodiment executes thecorrection of the parallel vibration only during the time period of theexposure. This is because if the correction of the parallel vibration isexecuted in addition to the correction of the angular vibration, a largeamount of stroke for the correction by the vibration correction unit6806 becomes necessary, resulting in needing a large-size vibrationcorrection unit 6806, which also results in degrading the operability ofthe exchangeable lens 6801.

Accordingly, the present exemplary embodiment executes the correction ofthe parallel vibration during a short time period of exposure period andreturns to a mode for executing the correction of the angular vibrationonly after the exposure period.

During time t8 and time t9, the present exemplary embodiment closes theshutter, opens the aperture of the diaphragm, and executes a mirror-downoperation of the quick return mirror (the state 3004 is in the “Hi”state). In addition, the present exemplary embodiment suspends thecalculation of the rotational radius L until the time t9 comes (thestate 3009 is in the “Lo” state) in order to prevent the degradation ofthe accuracy of calculating the rotational radius L, which may otherwiseoccur due to the saturation of the ACC because of the vibrationoccurring when the aperture of the diaphragm is increased, themirror-down operation of the quick return mirror is executed, or theshutter is closed as described above.

At time t9, the calculation of the rotational radius L is resumed (thestate 3009 shifts from the “Lo” state to the “Hi” state). At time t10,the user releases the full press of the release button 6804 a (theswitch S2 is in an “on” state) and the switch S2 shifts to thehalf-pressed state (the state 3003 shifts from the “Hi” state to the“Lo” state).

At time t11, after a full press of the release button 6804 a the switchS2 is in an “on” state again (the state 3003 shifts from the “Lo” stateto the “Hi” state). In synchronization with the full press of therelease button 6804 a, before time t12, the present exemplary embodimentincreases the aperture of the diaphragm of the exchangeable lens 6801,executes the mirror-up operation of the quick return mirror of thecamera 6804, and opens the shutter (the state 3004 shifts from the “Lo”state to the “Hi” state). Furthermore, the present exemplary embodimentsuspends the calculation of the rotational radius L (the state 3009shifts from the “Hi” state to the “Lo” state).

At time t12, the present exemplary embodiment starts the exposure (thestate 3005 shifts from the “Lo” state to the “Hi” state). Insynchronization with the start of the exposure, the correction of theparallel vibration is started (the state 3011 shifts from the “Lo” stateto the “Hi” state).

The present exemplary embodiment uses an average of the average valuesof the rotational radiuses L, which are calculated during the timeperiod from the time t2 to the time t3, the average values of therotational radiuses L, which are calculated during the time period fromthe time t5 to the time t6, and the average values of the rotationalradiuses L, which are calculated during the time period from the time t9to the time t11, as the rotational radius L in correcting the parallelvibration.

As described above, the rotational radius L is not reset during the timeperiod in which the release button 6804 a is being half-pressed (theswitch S1 is in an “on” state) and the average of the cumulativerotational radiuses L is calculated.

At time t13, the exposure ends (the state 3005 shifts from the “Hi”state to the “Lo” state). Furthermore, the correction of the parallelvibration also ends (the state 3011 shifts from the “Hi” state to the“Lo” state). During time t13 and time t14, the present exemplaryembodiment closes the shutter, releases the reduced aperture of thediaphragm, and executes the mirror-down operation of the quick returnmirror of the camera 6804 (the state 3004 is in the “Hi” state).

Furthermore, during the time period from time t11 to time t14, thecalculation of the rotational radius L is suspended (the state 3009 isin the “Lo” state). At time t14, the calculation of the rotationalradius L is resumed (the state 3009 shifts from the “Lo” state to the“Hi” state).

At time t15, the full press of the release button 6804 a (the switch S2is in an “on” state) is released. The release button 6804 a shifts tothe half-pressed state (the switch S1 is in an “on” state) (the state3003 shifts from the “Lo” state to the “Hi” state).

At time t16, the half-press of the release button 6804 a (the switch S1is in an “on” state) is released (the state 3002 shifts from the “Hi”state to the “Lo” state). In synchronization with the release of thehalf-press of the release button 6804 a, the present exemplaryembodiment suspends the calculation of the rotational radius L (thestate 3009 shifts from the “Hi” state to the “Lo” state).

Furthermore, the accumulated values of the rotational radiuses L, whichhave been used for calculating the average thereof, are reset because itis not verified whether the accumulated and calculated rotational radiusL can be used as they are for correcting the parallel vibration due tothe possible change in the method of holding the camera body 6804 at thetime when the photographer half-presses the release button 6804 a (whenthe switch S1 is in an “on” state). Accordingly, when the photographerhalf-presses the release button 6804 a again, the present exemplaryembodiment newly calculates a rotational radius L.

At time t17, which is the time after the time t16 by a predeterminedlength of time (e.g., four seconds), the operation of the gyro 6807 pand the ACC 101 p is suspended (the state 3008 shifts from the “Hi”state to the “Lo” state). Furthermore, the correction of the angularvibration is also suspended (the state 3010 shifts from the “Hi” stateto the “Lo” state).

At the time t15, as described above, the operation of the gyro 6807 pand the ACC 101 p and the correction of the angular vibration are notsuspended, to immediately execute the correction of the angularvibration when the photographer half-presses the release button 6804 aagain (the switch S1 is in an “on” state).

At time t18, the camera is powered off (the state 3001 shifts from the“Hi” state to the “Lo” state).

Although not illustrated in the timing chart of FIG. 30, the presentexemplary embodiment suspends the calculation of the rotational radius Lwhen the orientation of the camera has been greatly changed so as not touse the rotational radiuses L detected during the time period after theorientation of the camera has been greatly changed as inputs to thecalculation of the average of the rotational radiuses L. This is becauseif the camera is panned or if any operation which greatly changes theorientation of the camera is executed, the rotational radius may bechanged from the rotational radius at the time the photographer holdsthe camera to shoot an object, so that the calculated the rotationalradius L may degrade the accuracy in correcting the parallel vibration.

In this regard, the present exemplary embodiment resets thethus-accumulated rotational radiuses L if the output of the gyro 6807 phas exceeded a predetermined value (e.g., 3 deg/s) for a predeterminedlength of time (e.g., 0.5 seconds) and newly calculates the rotationalradius L when the output of the gyro 6807 p becomes low. Similarly, thepresent exemplary embodiment determines that the orientation of thecamera has been greatly changed if the output of the ACC 101 p exceeds apredetermined level of variation (e.g., 0.2 G) for a predeterminedlength of time (e.g., 0.5 seconds). Furthermore, the present exemplaryembodiment resets the thus-calculated rotational radiuses L and newlycalculates the rotational radius L when the variation of the output ofthe ACC 101 p becomes small.

If the photographer fully presses the release button 6804 a at the timet6 immediately after the detection of the rotational radius L hasstarted at the time t2, then the calculation of the rotational radius Lmay not be appropriately executed. In this case, the present exemplaryembodiment corrects the parallel vibration by using a predeterminedrotational radius L.

As described above, the rotational center of vibration differs with eachfrequency. In this regard, the rotational center of vibration lies atthe eyepiece unit of the camera at the high frequency, while at the lowfrequency, the rotational center of vibration lies around the waist ofthe photographer. The present exemplary embodiment utilizes the gainadjustment unit 311 having the characteristic illustrated in FIG. 21 inorder to acquire and calculate different rotational radius for differentfrequency levels.

Because the rotational center of vibration around the frequency of 5 Hzlies around the eyepiece unit of the camera, if no rotational radius Lis available, the present exemplary embodiment sets the distance fromthe eyepiece unit of the camera to the principal position of the imagingoptical system as an initial value of a rotational radius 3101 asillustrated in FIG. 31.

Referring to FIG. 31, the eyepiece unit of the camera is provided at theposition indicated by an arrow 3102. The present exemplary embodimentsets the distance from a rotation center 3104, which is positioned at anintersection of the position indicated by the arrow 3102 and an opticalaxis 3103, and a principal point 3105 of the imaging optical system asthe rotational radius 3101. This is because since the direction ofcorrection by the vibration correction unit is oriented in the directionorthogonal to the optical axis 3103, only the parallel vibrationcomponents in this direction are to be corrected.

If the photographer has fully pressed the release button 6804 a at thetime t6 immediately after half-press of the release button 6804 a at thetime t2, then the present exemplary embodiment corrects the parallelvibration by using the initial value. On the other hand, if it takessufficient time for the photographer to fully press the release button6804 a at the time t6 after half-press of the release button 6804 a atthe time t2, the present exemplary embodiment uses the calculatedrotational radius L.

Furthermore, the calculated rotational radius L may greatly vary due tothe influence from the state of holding the camera body. In this regard,if the photographer holds the camera in a state in which almost novibration occurs, then the output of the gyro may become very smallbecause almost no vibration occurs.

In this case, if a DC bias component is superposed on the velocityoutput calculated by integrating the output of the ACC 101 p and thus apredetermined level of output is input, the rotational radius Lcalculated by the expression (8) may have a very large value. In such acase, the present exemplary embodiment does not use the calculatedrotational radius L, but corrects the parallel vibration by using theinitial value of the rotational radius L. More specifically, if theangular velocity output is extremely small or the calculated rotationalradius is or exceeds a predetermined value (if the calculated rotationalradius is or exceeds the distance from the principal point of theimaging optical system to the waist of the photographer), then thepresent exemplary embodiment corrects the parallel vibration by usingthe initial value of the rotational radius L.

FIG. 32 is a flow chart illustrating an example of the above-describedconfiguration. The processing according to the flow of FIG. 32 startswhen the camera is powered on. In the example illustrated in FIG. 32,various control operations executed by the camera, such as a batterychecking operation, a photometry operation, a focus detection operation,the driving of the lens for AF, an operation for charging the flashunit, or an operation for capture, are omitted for easier understandingof the primary configuration of the present invention.

In the following exemplary flow, the angular vibration 6803 p of thecamera is detected by the gyro 6807 p and the parallel vibration 101 pbof the camera is detected by the ACC 101 p. In this regard, the sameflow is executed if the angular vibration 6803 y of the camera isdetected by the gyro 6807 y and the parallel vibration 101 yb of thecamera is detected by the ACC 101 y. Furthermore, if the camera ispowered off during any step of the flow chart of FIG. 32, then theprocessing in the flow chart ends.

Referring to FIG. 32, in step S3201, the lens CPU 6808 determineswhether the photographer has half-pressed the release button 6804 a (theswitch S1 is in an “on” state). If it is determined that thephotographer has half-pressed the release button 6804 a (the switch S1is in an “on” state) (YES in step S3201), then the processing advancesto step S3202.

In step S3202, the lens CPU 6808 activates the gyro 6807P and the ACC101 p and starts detecting vibration. At the same time, the lens CPU6808 activates the AF sensor (not illustrated) and starts detecting thefocusing state. In the present exemplary embodiment, the lens CPU 6808activates the gyro 6807P, the ACC 101 p, and the AF sensor (notillustrated) after the photographer has half-pressed the release button6804 a because the photographer orients the camera toward the object andthus the camera is in a stably-held state until the photographerhalf-presses the release button 6804 a.

In step S3203, the lens CPU 6808 determines whether an angular vibrationcorrection target value for the gyro 6807 p has been substantiallyacquired. If it is determined that an angular vibration correctiontarget value for the gyro 6807 p has been substantially acquired (YES instep S3203), then the processing advances to step S3204. On the otherhand, if it is determined that an angular vibration correction targetvalue for the gyro 6807 p has not been substantially acquired (NO instep S3203), then the processing advances to step S3228. This isintended so as to not correct the angular vibration until the integraloutput of the gyro 6807 p (the output of the HPF integration filter 301(FIG. 3)) becomes stable because it takes a specific amount of time(e.g., 0.5 seconds) before the stability of the integral output of thegyro 6807 p is achieved.

In step S3204, the lens CPU 6808 drives the vibration correction unit6806 and starts the correction of the angular vibration but does notcorrect the parallel vibration at this time. In step S3205, the lens CPU6808 determines whether AF has been completed. If it is determined thatAF has been completed (YES in step S3205), then the processing advancesto step S3206. On the other hand, if it is determined that AF has notbeen completed (NO in step S3205), then the processing advances to stepS3228.

Processing executed when it is determined in step S3205 that the AF hasnot been completed is described in detail.

In the step after it is determined in step S3205 that the AF has notbeen completed, (i.e., in step S3228), the present exemplary embodimentextracts desired frequency components from the output of the gyro 6807 pand the ACC 101 p and compares the extracted frequency components tocalculate the rotational radius as described above. Furthermore, thepresent exemplary embodiment cumulatively stores the rotational radiusesL that have been periodically calculated.

In step S3229, the lens CPU 6808 determines whether the detection of thefocusing state has been completed. If it is determined that thedetection of the focusing state has been completed (YES in step S3229),then the processing advances to step S3230. On the other hand, if it isdetermined that the detection of the focusing state has not beencompleted (NO in step S3229), then the processing advances to stepS3234.

In step S3234, the lens CPU 6808 determines whether the half-press ofthe release button 6804 a has been released (the switch S1 is in an“off” state). If it is determined that the half-press of the releasebutton 6804 a has been released (YES in step S3234), then the processingreturns to step S3201. In step S3201, the lens CPU 6808 waits until thephotographer half-presses the release button 6804 a. On the other hand,if it is determined that the half-press of the release button 6804 a hasnot been released (NO in step S3234), then the processing returns tostep S3203. In step S3203, the lens CPU 6808 determines whether anangular vibration correction target value for the gyro 6807 p has beensubstantially acquired (whether the angular vibration can be corrected).

If it is determined again in step S3203 that the angular vibrationcannot be corrected (NO in step S3203), then the processing advances tostep S3228. In step S3229, the lens CPU 6808 determines again whetherthe detection of the focusing state has been completed.

Furthermore, if the correction of the angular vibration is ready, thenthe processing advances from step S3203 to step S3204. In step S3204,the lens CPU 6808 starts the correction the correction of the angularvibration. In step S3205, the lens CPU 6808 determines whether the AFhas been completed. If the flow advances in the above-described manner,AF has not been completed. Accordingly, the processing advances to stepS3228. In step S3229, the lens CPU 6808 determines again whether thedetection of the focusing state has been completed.

If it is determined that the detection of the focusing state has beencompleted (YES in step S3229), then the processing advances to stepS3230. In step S3230, the lens CPU 6808 suspends the detection of therotational radius L in order to prevent acquiring an inappropriaterotational radius L due to superposition, on the ACC output, of noisethat may occur due to the driving of the lens for focusing, which is tobe executed in the subsequent steps.

In step S3231, the lens CPU 6808 drives the lens for focusing. In stepS3232, the lens CPU 6808 determines whether the driving of the lens hasbeen completed. If it is determined that the driving of the lens hasbeen completed (YES in step S3232), then the processing advances to stepS3233. In step S3233, the lens CPU 6808 stops the driving of the lens.

On the other hand, if it is determined that the driving of the lens hasnot been completed (NO in step S3232), then the processing advances fromstep S3232 to steps S3234 and S3203, and then returns to step S3228 oradvances from step S3232 to steps S3234, S3203, S3404, and S3205, andthen returns to step S3228. Thus, the lens CPU 6808 executes theabove-described steps as loop processing and waits until the driving ofthe lens is completed unless the half-press of the release button 6804 ais released.

In step S3234, the lens CPU 6808 determines whether the half-press ofthe release button 6804 a has been released after stopping the drivingof the lens in step S3233. If it is determined that the half-press ofthe release button 6804 a has not been released (NO in step S3234), thenthe processing returns to step S3203. In this case, the processingadvances from step S3203 to steps S3204 and S3205. In step S3205, thelens CPU 6808 determines whether AF has been completed. If it isdetermined that AF has been completed (YES in step S3205), then theprocessing advances to step S3206. On the other hand, if it isdetermined that AF has not been completed (NO in step S3205), then theprocessing returns to step S3228, in which the lens CPU 6808 executesthe focusing operation again.

In step S3206, the lens CPU 6808 cumulatively detects and stores theperiodically calculated rotational radius L as in step S3228 in theabove-described manner. If the processing has advanced from step S3228to step S3206, the processing in step S3206 is not particularly executedbecause the rotational radius L has already been started in step S3228.

In step S3207, the lens CPU 6808 determines whether the camera is beingpanned. More specifically, with respect to the method of determining thepanning status of the camera, the lens CPU 6808 determines that thecamera is being panned (vibrated in a specific direction) if the outputof the gyro 6807 p has an angular velocity of a predetermined level(e.g., 3 deg/s) or larger for a predetermined time period (e.g., 0.5seconds) or longer. Alternatively, the lens CPU 6808 can determine thatthe camera is being panned if the integral value of the gyro 6807 p (theoutput of the HPF integration filter 301) has a predetermined angle(e.g., 1.5 deg) or larger for a predetermined amount time period (e.g.,0.2 seconds) or longer.

If it is determined that the camera is being panned (YES in step S3207),then the processing advances to step S3208. On the other hand, if it isdetermined that the camera is not being panned (NO in step S3207), thenthe processing advances to step S3211.

In step S3208, the lens CPU 6808 suspends the detection of therotational radius L and the correction of the angular vibration in adirection indicated by the arrow 6803 p (FIG. 2). This is because whenthe camera is being panned, the rotational radius L cannot be detectedwith high accuracy since vibration is not constant during panning. Inaddition, this is because the vibration angle is large during panningand thus the correction lens may reach the mechanical end if thecorrection of the angular vibration is executed, resulting in adegradation of accuracy in correcting image shake in the directionindicated by the arrow 6803 y (FIG. 1) due to the mechanicalrestriction.

In step S3209, the lens CPU 6808 determines again whether the camera isbeing panned. If it is determined that the camera is being panned (YESin step S3209), then the processing advances to step S3211.

On the other hand, if it is determined that the panning has ended (NO instep S3209), then the processing advances to step S3210. In step S3210,the lens CPU 6808 resumes the detection of the rotational radius L andalso resumes the correction of the angular vibration since the camera isbeing stably held by the photographer.

In step S3211, the lens CPU 6808 determines whether the half-press ofthe release button 6804 a has been released (the switch S1 is in an“off” state). If it is determined that the half-press of the releasebutton 6804 a has been released, then the processing advances to stepS3235. On the other hand, if it is determined that the half-press of therelease button 6804 a has not been released (NO in step S3211), then theprocessing advances to step S3212.

In step S3235, the lens CPU 6808 suspends the detection of therotational radius L and resets the rotational radiuses L that have beencumulatively stored. Then, the processing advances to step S3225. Thisis because it is predicted that the capture condition is to be changedby shifting to capture of a different object or that the capture is toend since the half-press of the release button 6804 a has been released.However, it is also useful if the lens CPU 6808 does not reset thestored rotational radius L if the photographer half-presses the releasebutton 6804 a again immediately after the release thereof (if thephotographer half-presses the release button 6804 a again within onesecond from the release thereof, for example).

In step S3225, the lens CPU 6808 waits for a predetermined length oftime (e.g., four seconds). During the waiting period, the correction ofthe angular vibration is continued and both the gyro 6807 p and the ACC101 p continue to operate. The lens CPU 6808 continues the correction ofthe angular vibration for a specific time period after the release ofthe release button 6804 a in order to prepare to immediately respondwhen the photographer half-presses the release button 6804 a again.

After the predetermined length of time has elapsed, the processingadvances to step S3226. In step S3226, the lens CPU 6808 suspends theoperation of the gyro 6807 p and the ACC 101 p. Then, the processingreturns to step S3201.

If it is determined in step S3211 that the release button 6804 a hasbeen continuously half-pressed (YES in step S3211), then the processingadvances to step S3212. In step S3212, the lens CPU 6808 determineswhether the release button 6804 a has been fully pressed (the switch S2is in an “on” state). If it is determined that the release button 6804 ahas not been fully pressed (NO in step S3212), then the processingreturns to step S3207 and repeats the above-described processing in stepS3207 and beyond. More specifically, the lens CPU 6808 waits until thecapture starts while correcting the angular vibration, detecting therotational radius L, and determining whether the camera is being panned.

On the other hand, if it is determined that the release button 6804 ahas been fully pressed to start capture (YES in step S3212), then theprocessing advances to step S3213. In step S3213, the lens CPU 6808suspends the operation for averaging the detected rotational radiuses Lin order to prevent otherwise possible degradation of the accuracy ofdetecting the rotational radius L, which may occur due to disturbanceapplied on the ACC 101 p during a vibration generating operation such asa mirror-up (or down) operation of the quick return mirror, increasingor decreasing of the aperture of the diaphragm, or the shutteropening/closing operation. In addition, the lens CPU 6808 averages therotational radiuses L that have been detected during each period (theperiods 2703 and 2704 (FIG. 27)).

In step S3214, the lens CPU 6808 determines whether the calculatedrotational radius L is appropriate. If it is determined that thecalculated rotational radius L is appropriate (YES in step S3214), thenthe processing advances to step S3215. On the other hand, if it isdetermined that the calculated rotational radius L is not appropriate(NO in step S3214), then the processing advances to step S3236.

The determination in step S3214 as to whether the calculated rotationalradius L is appropriate is executed as to the following three points:

i) whether the length of the time period for detecting the rotationalradius L is short,

ii) whether the calculated rotational radius L is greater than apredetermined value,

iii) whether the state in which the angular velocity is less than orequal to a predetermined level has continued for a specific long periodof time.

With respect to the point (i), the lens CPU 6808 determines that theresult of calculating the rotational radius L is not appropriate if thelength of time for calculating the rotational radius L is not longenough because the length of the time period is short from the time atwhich it is determined that the release button 6804 a has beenhalf-pressed in step S3201 to the time at which it is determined thatthe release button 6804 a has been fully pressed in step S3212.

With respect to the point (ii), the lens CPU 6808 determines that theresult of calculating the rotational radius L is not appropriate if thedetected rotational radius L exceeds a predictable upper limit value(e.g., an estimate of the distance from the principal point of thephotographic lens to the waist of a typical photographer) due to a causesuch as disturbance.

With respect to the point (iii), the lens CPU 6808 determines that theresult of calculating the rotational radius L is not appropriate if theangular velocity output (or the angle output calculated by integratingthe angular velocity output) is smaller than a predetermined valuebecause the camera is in a stable state on a tripod. This is because ifthe rotational radius L is calculated by using the expression (8) inthis state, an extremely great rotational radius L may be acquired dueto a calculation error.

The rotational radius L of the initial value is not limited to thedistance from the eyepiece unit of the camera to the principal point ofthe imaging optical system. That is, a value “0” can be used, forexample. In this case, the parallel vibration is not corrected.

In the present exemplary embodiment, the rotational radius L iscalculated before starting capture. Furthermore, the method is primarilydescribed in which the output correction unit 309 corrects the output ofthe gyro based on the averaged rotational radius L. However, if the realtime correction method, in which the rotational radius L is calculatedand the output correction unit 309 corrects the output of the gyro, isused, and if any of the above-described conditions 1) through 3) issatisfied, it is useful to calculate an initial value as the rotationalradius L.

Furthermore, if the method in which the rotational radius L ispreviously calculated is used or if the above-described real timecorrection method is used, the present exemplary embodiment does notcalculate a rotational radius L with the comparison unit 308 if a drivemechanism such as a lens driving unit, a diaphragm, a mirror, or ashutter is driven.

However, if the calculation of the rotational radius L is continuedwhile the drive mechanism is currently operated and if theabove-described condition 2) is satisfied (if the rotational radius L isgreater than a predetermined value), or if the drive mechanism is beingoperated, then the correction reliability determination unit determinesthat the output of the comparison unit is not appropriate. In this case,it is useful if the initial value is used as the rotational radius L.

If it is determined that the calculated rotational radius L is notappropriate in step S3214 (NO in step S3214), then the processingadvances to step S3236. In step S3236, the lens CPU 6808 uses arotational radius provided as an initial value for the rotational radiusL if the camera is in the above-described state. Here, the rotationalradius L provided as the initial value refers to the distance from theeyepiece unit of the camera to the principal point of the imagingoptical system as illustrated in FIG. 31.

In step S3215, the lens CPU 6808 determines whether the camera is beingpanned as in step S3207. If it is determined that the camera is beingpanned (YES in step S3215), then the processing advances to step S3217.On the other hand, if it is determined that the camera is not beingpanned (NO in step S3215), then the processing advances to step S3216.

If it is determined that the camera is being panned in step S3215, thelens CPU 6808 has already suspended the correction of the angularvibration in step S3208. Accordingly, the correction of the angularvibration is not currently executed.

In step S3217, the lens CPU 6808 starts a charge accumulation operationwith the image sensor 6805. However, because the shutter is not openedat this time, the light flux of the actual object has not been incidentto the image sensor 6805 yet.

In step S3218, the lens CPU 6808 executes the mirror-up operation of thequick return mirror, drives the diaphragm of the lens, and opens theshutter. As described above, the lens CPU 6808 starts the accumulationof the light flux of the object to be formed on the image sensor 6805.

In step S3219, the lens CPU 6808 waits until a capture time periodappropriate for exposure comes. In step S3220, the lens CPU 6808suspends the correction of the parallel vibration after the exposure iscompleted.

In this case, the suspension of the correction of parallel vibration isnot executed since the processing in step S3216, (which is to bedescribed in detail below), is skipped because it is determined that thecamera is being panned in step S3215 (in this case, the correction ofthe parallel vibration has not been executed in this case). In stepS3221, the lens CPU 6808 closes the shutter, drives the diaphragm of thelens to the initial state, and executes the mirror-down operation of thequick return mirror.

As described above, if it is determined that the camera is being pannedin step S3215, the lens CPU 6808 executes control for capture withoutcorrecting the angular vibration or the parallel vibration.

On the other hand, if it is determined that the camera is not beingpanned (NO in step S3215), then the processing advances to step S3216.In step S3216, the lens CPU 6808 starts the correction of the parallelvibration according to the rotational radius calculated in step S3213.In step S3217, the lens CPU 6808 starts the charge accumulation on theimage sensor 6805 and repeats the processing from step S3218 to stepS3221.

As described above, if it is determined that the camera is not beingpanned in step S3215, it is determined that the correction of theangular vibration has been executed in step S3204 or that the correctionof the angular vibration has been resumed in step S3210. Accordingly,during the exposure (during the accumulation of the light flux from theobject), the lens CPU 6808 executes both the correction of the angularvibration and the correction of the parallel vibration.

In step S3222, the lens CPU 6808 displays information acquired by theimage sensor 6805 on a liquid crystal display (LCD) monitor provided onthe back side of the camera and records the information on a recordingmedium. In step S3223, the lens CPU 6808 determines whether the fullpress of the release button 6804 a is released (i.e., waits until thefull press of the release button 6804 a is released).

If it is determined that the full press of the release button 6804 a isreleased (YES in step S3223), then the processing advances to stepS3224. In step S3224, the lens CPU 6808 determines whether thehalf-press of the release button 6804 a has been released. If it isdetermined that the half-press of the release button 6804 a has not beenreleased (NO in step S3224), then the processing returns to step S3206,in which the lens CPU 6808 repeats the above-described processing instep S3206 and beyond. More specifically, in this case, the lens CPU6808 detects the rotational radius L until the half-press of the releasebutton 6804 a is released while waiting for the release button 6804 a tobe fully pressed. In steps S3225 and beyond, the lens CPU 6808 executesthe above-described processing.

An operation executed for starting the correction of the angularvibration in step S3204 and the correction of parallel vibration in stepS3216 is described in detail below.

FIG. 33 is a block diagram illustrating an example of a signalprocessing system. Details of an exemplary operation for inputting theangular vibration correction target value and the parallel vibrationcorrection target value to the driving unit 6809, which drives thevibration correction unit 6806, are described below with reference toFIG. 33.

In the example illustrated in FIG. 33, blocks provided upstream of thesensitivity adjustment unit 303, which is configured to output anangular vibration correction target value, and the output correctionunit 309, which is configured to output the parallel vibrationcorrection target value, are omitted. In the example illustrated in FIG.33, a sample holding (S/H) unit 3302 and a differential unit 3303 areillustrated as analog blocks for easier illustration and understandingalthough the entire operation to be described here is executed bycalculation using software.

The angular vibration correction target value output from thesensitivity adjustment unit 303 is input to a variable gain unit 3301.The variable gain unit (variable gain amplifier) 3301 changes the gainof the angular vibration correction target value from “0” to “1” in 0.5seconds when a “switch S1 on” signal 3304 is input by the half-press ofthe release button 6804 a.

Thus, the accuracy of correcting the angular vibration can increaseafter 0.5 seconds of the half-press of the release button 6804 a. In thepresent exemplary embodiment, the gain is minutely and gradually changedin order to prevent the photographer from perceiving a large anomaly onthe screen of the finder according to the current state of the handshake if the correction of the image shake rapidly starts immediatelyafter the half-press of the release button 6804 a. The operation forchanging the gain is described in detail below with reference to FIG.34.

To prevent a rapid variation of the screen of the finder that mayotherwise occur due to rapid suspension of the correction of the imageshake, the variable gain amplifier 3301 changes the gain of the angularvibration correction target value from “1” to “0” in 0.5 seconds afterthe elapse of a predetermined time period (e.g., four seconds) after therelease of the half-press of the release button 6804 a in order toprevent a rapid variation of the screen of the finder that may otherwiseoccur due to rapid suspension of the correction of the image shake.

In the present exemplary embodiment, the lens CPU 6808 suspends thecorrection of the image shake after elapse of a predetermined timeperiod from the half-press of the release button 6804 a, as describedabove, in order to prepare for continuing the correction of the imageshake if the release button 6804 a is half-pressed again, as describedabove in step S3225 (FIG. 32).

The parallel vibration correction target value output from the outputcorrection unit 309 is input to both the S/H unit 3302 and thedifferential unit 3303. The differential unit 3303 outputs adifferential value between the output of the S/H unit 3302 and theparallel vibration correction target value.

More specifically, the output from the S/H unit 3302 is “0” becauseduring sampling, the two signals input to the differential unit 3303 areequivalent to each other. A “switch S2 on” signal 3305, which is outputwhen the release button 6804 a is fully pressed, is also input to theS/H unit 3302. When the “switch S2 on” signal 3305 is input, the S/Hunit 3302 sample-holds the parallel vibration correction target value.

Accordingly, at this point in time, the output of the S/H unit 3302 isfixed. Furthermore, in this case, the output of the differential unit3303 is output serially and continuously from “0” in synchronizationwith the full press of the release button 6804 a (the input of the“switch S2 on” signal 3305). The output of the differential unit 3303 isdescribed in detail below with reference to the waveform illustrated inFIG. 34.

Furthermore, an exposure completion signal 3306 is also input to the S/Hunit 3302. When the exposure completion signal 3306 is input to the S/Hunit 3302, the S/H unit 3302 sample-holds the parallel vibrationcorrection target value again. Accordingly, the output of thedifferential unit 3303 becomes “0” in synchronization with thecompletion of the exposure.

FIG. 34 illustrates the above-described processing with a vibrationwaveform. In the example illustrated in FIG. 34, the elapsed time isshown on the horizontal axis. The amount of vibration on the image planecalculated by converting the amount of vibration or the correctionamount thereof is shown on the vertical axis.

In the example illustrated in FIG. 34, timings t2, t6, t8, t9, t16, t17are similar to those illustrated in FIG. 30.

Referring to FIG. 34, a waveform 3401 indicates the amount of vibrationon the image plane that may occur due to the angular vibration and theparallel vibration, which is indicated as a cosine wave for easierunderstanding. A waveform 3402 indicates a component, of the waveform3401, of the amount of vibration on the image plane that may occur dueto the angular vibration. A waveform 3403 indicates a component, of thewaveform 3401, of the amount of vibration on the image plane that mayoccur due to the parallel vibration.

A waveform 3404 indicates a conversion value of the angular vibrationcorrection target value output from the variable gain amplifier 3301(FIG. 33) on the image plane, which is the target value of correctingthe vibration indicated with the waveform 3402. As can be seen from thewaveform 3404, the present exemplary embodiment acquires an appropriategain of the angular vibration correction target value in a predeterminedtime (e.g., 0.5 seconds) from the half-press of the release button 6804a (the time t2).

On the waveform 3402, a predetermined vibration amount 3307 is acquiredat time t2. If the correction of the image shake is started in thisstate, then the vibration correction unit 6806 is rapidly driven fromthe “0” position. In this case, the finder screen may be greatlyvibrated. To prevent this, the present exemplary embodiment graduallysets the gain of the angular vibration correction target value to anappropriate value at time t2 as illustrated with the waveform 3404.

Furthermore, when the half-press of the release button 6804 a isreleased at time t16 and four seconds passes after that, namely, at timet17, the present exemplary embodiment gradually reduces the gain of theangular vibration correction target value to finally cause the gain toconverge at “0”.

On the waveform 3402, a predetermined vibration amount 3308 is acquiredat time t17. If the correction of the image shake is rapidly suspended,then the vibration correction unit 6806 is rapidly driven from thecorrection position to the “0” position. In this case, the finder screenmay be greatly vibrated. In this regard, the present exemplaryembodiment prevents the rapid variation on the screen by graduallyreducing the gain from time t17.

A waveform 3405 indicates a value acquired by converting the parallelvibration correction target value output from the differential unit 3303(FIG. 33) on the image plane. The waveform 3405 is a target value forcorrecting the vibration indicated with the waveform 3403.

As described above, the output of the differential unit 3303 is seriallyand continuously output from “0”. That is, the waveform 3405 isdifferent from an output 3309 at time t6 on the waveform 3403.Accordingly, the present exemplary embodiment can prevent failure ofappropriately correcting the parallel vibration when the vibrationcorrection unit 6806 cannot respond before the start of the exposure ifthe correction of the vibration rapidly starts as illustrated with theoutput 3309 at time t6.

As described above with reference to FIG. 33, when the exposure ends,the lens CPU 6808 causes the S/H unit 3302 to start sample-holdingagain. In this case, the output of the differential unit 3303 becomes“0”. Accordingly, the output of the parallel vibration correction targetvalue becomes “0” when the exposure ends at time t8.

In this regard, although the vibration correction unit 6806 suspends thecorrection of the parallel vibration, the image is not affected becausethe exposure has already been completed. Furthermore, because themirror-up operation is currently being executed, the rapid suspension ofthe correction of the parallel vibration cannot be perceived by thephotographer on the screen.

To prevent the photographer from perceiving unnatural vibration on thescreen, it is useful if the start and the suspension of the correctionof the image shake are continuously executed. In this regard,particularly when the screen cannot be viewed by the photographer asdescribed above, the present exemplary embodiment quickly prepares for asubsequent operation by rapidly suspending the correction of theparallel vibration.

At time t9, the mirror-up operation of the quick return mirror iscompleted (the shutter has already been completed at time t8). At thispoint in time, a predetermined time (e.g., 100 ms) has already elapsedsince the suspension of the correction of the parallel vibration.Accordingly, a anomaly on the screen occurring due to the suspension ofthe correction of the parallel vibration cannot be recognized by thephotographer.

A waveform 3406 indicates a value of the amount of driving of thevibration correction unit 6806 converted on the image plane. Thewaveform 3406 is roughly equivalent to a combined waveform of thewaveform 3404 and the waveform 3405.

With respect to the driving amount of the vibration correction unit6806, the correction of the angular vibration gradually starts at timet2. In addition, the correction of the angular vibration and thecorrection of the parallel vibration serially start at time t6.

At time t8, the lens CPU 6808 suspends the correction of the parallelvibration. At time t9, the lens CPU 6808 executes the mirror-downoperation of the quick return mirror. At time t16, the half-press of therelease button 6804 a is released. At time t17, which is a time fourseconds after the time t16, the lens CPU 6808 starts the suspension ofthe correction of the angular vibration.

As described above, the lens CPU 6808 executes control to serially startthe correction of the angular vibration and the correction of theparallel vibration. Accordingly, the vibration correction unit 6806 canalways securely execute the correction of image shake.

As described above, the lens CPU 6808 suspends the operation foraveraging the detected rotational radiuses L in step S 3213, to preventotherwise possible degradation of the accuracy of detecting therotational radius L, which may occur due to disturbance applied on theACC 101 p during a vibration generating operation such as a mirror-up(or down) operation of the quick return mirror, increasing or decreasingof the aperture of the diaphragm, or the shutter opening/closingoperation. This phenomenon is described in detail below with referenceto FIG. 35.

FIG. 35 illustrates an example of a waveform of the ACC 101 p when thequick return mirror is operated and the shutter is driven. In theexample illustrated in FIG. 35, the elapsed time is shown on thehorizontal axis. The output voltage of the ACC 101 p is placed on thevertical axis.

Referring to FIG. 35, the ACC 101 p is driven at a voltage of 5 V. Anoutput waveform 3501 is superposed with a bias voltage 3505 comparedwith a reference voltage 3502. The bias voltage 3505 indicates that theACC 101 p is subjected to gravity of 1 G.

The 1 G gravity is always applied on the ACC 101 p (FIG. 31) to detectthe parallel vibration (or the rotational radius L). Accordingly, theacceleration output equivalent to 1 G gravity is output as the biasvoltage 3505. The acceleration outputable voltage of the ACC 101 pranges from 0.5 to 4.5 V as represented in FIG. 35 by broken lines 3503and 3054. The output may be saturated outside the range.

With respect to the waveform 3501 of the ACC 101 p, the accelerationdetectable range of the ACC 101 p has become narrow due to the biasvoltage 3505, which is equivalent to the 1 G gravity. Furthermore, alarge vibration acceleration is applied to the ACC 101 p due to thedriving of the quick return mirror, the shutter, or the diaphragm.Accordingly, in waveform segments 3501 a, 3501 b, and 3501 c, the outputis saturated at the timing of driving of the mirror and the shutter.

This problem can be solved by using an ACC having a wide detectionrange. However, if such an ACC is used, parallel vibration accelerationcannot be detected with high accuracy because the accuracy of detectinga microacceleration of such an ACC is low. Accordingly, instead of usingan ACC having a wide detection range but whose micro-accelerationdetection accuracy is low, in the present embodiment the rotationalradiuses L acquired during time periods other than the time periods inwhich the quick return mirror, the shutter, or the lens is driven areaveraged and the average of such the rotational radiuses L is used. Thepresent embodiment is believed to provide an accuracy of correcting theparallel vibration that is higher than that in the case of using an ACChaving a wide detection range.

In this regard, the present exemplary embodiment uses an ACC, as the ACC101 p, which is capable of detecting the parallel vibration with highaccuracy although whose detection range is restricted due to possiblesaturation of the acceleration output (i.e., as described above, theacceleration output in the time period of the saturation is not to beused as described above), which may occur when the quick return mirror,the shutter, the diaphragm, or the lens is driven.

As described above with reference to FIG. 11, the rotational radius Lrefers to the distance from the rotational center 1102 p to the ACC 101p. The distance is equivalent to the distance from the rotational center1102 p to the principal point of the imaging optical system because theACC 101 p is disposed at the principal point of the imaging opticalsystem.

A parallel vibration may occur due to the displacement of the principalpoint of the imaging optical system. Accordingly, the displacement ofthe principal point of the imaging optical system can be calculated bymultiplying the rotational radius L by the angle output, which iscalculated by integrating the output of the gyro 6807 p. Thus, thepresent exemplary embodiment can calculate the parallel vibrationcorrection target value.

Meanwhile, although not described above, the position of the lens on theoptical axis actually changes due to the operation for focusing on theobject. Due to the change of the lens position on the optical axis, theprincipal point of the imaging optical system may be displaced from thelocation of installation of the ACC 101 p. Accordingly, in order tocalculate the displacement of the principal point of the imaging opticalsystem, it is necessary to correct the rotational radius L according tothe displacement between the principal point of the imaging opticalsystem and the installation location of the ACC 101 p.

FIGS. 36 and 37 each illustrate the state of the camera that is vibratedin the above-described case. In the examples illustrated in FIGS. 36 and37, the distance between the lens and the object 3601 is different fromthe distance between the lens and the object 3701.

Referring to FIG. 36, when the photographer desires to photograph anobject 3601, a principal point A 3602 of the entire imaging opticalsystem exists at the same position as that of the ACC 101 p on theoptical axis when the imaging optical system is driven and adjusted tothe focusing position. Accordingly, the lens CPU 6808 calculates therotational radius L 1101 p according to the output of the ACC 101 p andthe output of the gyro 6807 p. Furthermore, the lens CPU 6808 calculatesa parallel vibration amount 3603 using the rotational radius L 1101 pand the output of the gyro 6807 p by calculation with the second term ofthe right side of the expression (4).

Referring to FIG. 37, the object 3701 is more distant from the lenscompared with the object 3601 (FIG. 36). A principal point B 3702 of theentire imaging optical system is displaced from the installationlocation of the ACC 101 p by a displacement amount 3704 when the imagingoptical system is driven and adjusted to the focusing position.Accordingly, in this case, if the rotational radius L 1101 p were to becalculated based on the output of the ACC 101 p and the output of thegyro 6807 p, the parallel vibration amount 3703 at the lens principalpoint in FIG. 37 could not be calculated.

In this regard, the lens CPU 6808 calculates a modified rotationalradius 3705 by subtracting a displacement amount 3704 from therotational radius L 1101 p, which is calculated based on the output ofthe ACC 101 p and the output of the gyro 6807 p. Furthermore, the lensCPU 6808 calculates the parallel vibration amount 3703 at the lensprincipal point B 3702 by a calculation using the second term of theright side of the expression (4) based on the modified rotational radiusL 3705 and the output of the gyro 6807 p. Thus, the lens CPU 6808corrects the rotational radius L according to the object distance.

To calculate the parallel vibration at the principal point of thephotographic lens, it is beneficial to dispose the ACC 101 p at theprincipal point. Accordingly, it becomes unnecessary to execute theabove-described correction processing if the installation location ofthe ACC 101 p can be changed even if the principal point of thephotographic lens is changed due to the focusing operation.

In this regard, for example, if the ACC 101 p is mounted on the lens,which is to be moved towards the object side during focusing, the amountof movement of the principal point and that of the ACC can be madeidentical to each other. However, in this case, the configuration of theimaging optical system may become complicated. In addition, the size ofthe entire lens unit may become large.

In this regard, by executing the correction described with reference toFIG. 37, the parallel vibration amount at the principal point, which maychange, can be calculated when the ACC 101 p is fixedly mounted on thecamera. The correction can be executed by detecting the position of thefocusing lens with a focus encoder, calculating the principal point ofthe imaging optical system based on the detection result, andcalculating the displacement with the installation location of the ACC101 p.

The output correction unit 309 (FIG. 3) calculates the parallelvibration correction target value by multiplying the angle output whosegain has been adjusted by the rotational radius L and the imagingmagnification. In addition, the output correction unit 309 also correctsthe rotational radius L in the above-described manner.

FIG. 38 is a block diagram illustrating an exemplary inner configurationof the output correction unit 309 according to the present exemplaryembodiment. Referring to FIG. 39, an imaging magnification calculationunit 309 b calculates the imaging magnification based on informationabout the lens zoom position and the lens focusing position from a lensencoder included in the zoom and focus information 302.

A displacement calculation unit 309 d calculates the displacementbetween the principal point of the imaging optical system and theinstallation location of the ACC based on the zoom and focus information302 at the same time. Information about the rotational radius Lcalculated by the comparison unit 308 is corrected within the outputcorrection unit 309 by using a rotational radius correction unit 309 cbased on the output from the displacement calculation unit 309 d.Accordingly, the rotational radius L is corrected to the rotationalradius L from the principal point of the imaging optical system to therotational center at the current time, instead of the rotational radiusL from the installation location of the ACC 101 p to the rotationalcenter.

An output correction unit 309 a multiplies the output of the gainadjustment unit 311 by the corrected rotational radius L and the imagingmagnification to calculate the parallel vibration correction targetvalue. The rotational radius L is corrected at the timing of executingthe processing in step S3213 (FIG. 32).

In step S3213, the lens CPU 6808 calculates the corrected rotationalradius L from the principal point of the imaging optical system to therotational center by subtracting the average value of the rotationalradius L from the installation location of the ACC 101 p to therotational center from the distance between the installation location ofthe ACC 101 p to the principal point of the imaging optical system underthe capture condition. In step S3214, the lens CPU 6808 determineswhether the calculated corrected rotational radius L is accurate. Instep S3216, the lens CPU 6808 uses the corrected rotational radius L tocorrect the parallel vibration.

With the configuration illustrated in FIG. 38, the installation locationof the ACC 101 p can be freely determined and the ACC 101 p can beinstalled at a position different from the position in the vicinity ofthe principal point of the imaging optical system. In addition, with theabove-described configuration, the present exemplary embodiment canexecute simple correction to correct the vibration even if the principalpoint of the imaging optical system is changed.

Furthermore, the present exemplary embodiment having the above-describedconfiguration can suppress or at least reduce the influence from thegravitational error superposed on the ACC and the influence fromdrifting of the camera by using the frequency band used for comparisonof the output of the gyro and the ACC that is narrower than the bandused for correcting the vibration. Accordingly, the present exemplaryembodiment can implement a small-sized image stabilization system havinga high mobility and operability, which stably operates in the case ofmacro capture by a camera or a video camera and capable of correctingthe parallel vibration with high accuracy.

A second exemplary embodiment of the present invention is describedbelow. In the above-described first exemplary embodiment, the gain ofthe output of the gyro (integral angle output) used for correcting theparallel vibration is adjusted by the gain adjustment unit 311 for eachfrequency in order to suppress the influence from the change ofrotational radiuses L occurring in relation to the vibration frequencyas illustrated in FIG. 20.

In this regard, the rotational radius L does not always depend on thefrequency as illustrated in FIG. 20 in all cases. For example, if thephotographer holds the camera while crouching himself or if thephotographer executes capture while fixing his elbow (on a desk, forexample), the gain of the rotational radius L does not increase (therotational radius L does not become long) as the frequency becomes loweras illustrated in FIG. 20.

If the gain adjustment unit 311 is used in this case, the parallelvibration in the low frequency is over-corrected. As a result, in thiscase, the amount of vibration may increase in the frequency band.

In this regard, in the present exemplary embodiment, the change of therotational radius L is detected for each frequency and the lens CPU 6808determines whether the gain adjustment unit 311 is to be used accordingto a result of the detection.

FIG. 39 is a block diagram illustrating an exemplary configuration of animage stabilization control apparatus included in a single-lens reflexcamera according to the present exemplary embodiment. The externalappearance of the camera is similar to that illustrated in FIGS. 1 and2.

The image stabilization control apparatus according to the presentexemplary embodiment includes a BPF unit(s) for the gyro 6807 p, a BPFunit(s) for the ACC 101 p, and a unit configured to determine whether toadjust the rotational radius L for each frequency in addition to theconfiguration of the image stabilization control apparatus (FIG. 3)according to the first exemplary embodiment, to recognize the tendencyof the variation of the rotational radius L for each frequency. Inaddition, the image stabilization control apparatus according to thepresent exemplary embodiment includes an input switching unit. The inputswitching unit is configured to control the execution of adjustment ofthe rotational radius L for each frequency after determining whether therotational radius L is to be adjusted for each frequency.

Referring to FIG. 39, a gyro BPF 1 unit 3901 is a filter for extractingan angular velocity output at the frequency of 5 Hz as the gyro BPF unit306 (FIG. 3). An ACC BPF 1 unit 3902 is a filter for extracting avelocity output at the frequency of 5 Hz as the ACC BPF unit 307 (FIG.3).

A comparison unit 3905 calculates a rotational radius L at 5 Hz based onthe angular velocity output and the velocity output. A gyro BPF 2 unit3903 is a filter for extracting an angular velocity output at 1 Hz. AnACC BPF 2 unit 3904 is a filter for extracting a velocity output at 1Hz.

A comparison unit 3906 calculates a rotational radius L at 1 Hz based onthe angular velocity output and the velocity output. An adjustmentavailability determination unit 3907 compares the outputs of thecomparison unit 3905 and the comparison unit 3906.

As described above in the first exemplary embodiment, generally, therotational radius L in a high frequency is smaller than that in a lowfrequency. Accordingly, if the rotational radius L at 5 Hz, which is theoutput of the comparison unit 3905, is smaller than the rotationalradius L at 1 Hz, which is the output of the comparison unit 3906, theadjustment availability determination unit 3907 determines that thecamera is in the state described above in the first exemplaryembodiment.

In this case, the adjustment availability determination unit 3907outputs the result to the input switching unit 3908. The input switchingunit 3908 outputs the output of the gain adjustment unit 311 to theoutput correction unit 309. In the above-described manner, theadjustment availability determination unit 3907 generates a parallelvibration correction target value, which is equivalent to the rotationalradius L that changes frequency to frequency.

If the rotational radius L at 1 Hz, which is the output of thecomparison unit 3906, and the rotational radius L at 5 Hz, which is theoutput of the comparison unit 3905, are the same or if the rotationalradius L at 5 Hz is greater than the rotational radius L at 1 Hz, thenthe adjustment availability determination unit 3907 determines that thecamera is in a state different from the state described above in thefirst exemplary embodiment.

The adjustment availability determination unit 3907 outputs the resultto the input switching unit 3908. The input switching unit 3908 outputsthe output of the HPF integration filter 301 to the output correctionunit 309. More specifically, the adjustment availability determinationunit 3907 generates a parallel vibration correction target value thatbypasses the gain adjustment unit 311.

As described above with reference to FIG. 22, the output of the HPFintegration filter 310 has a characteristic different from that of anormal HPF integration filter 301 to correct the characteristic of thegain adjustment unit 311. Accordingly, the present exemplary embodimentdoes not use the output of the HPF integration filter 310. With theabove-described configuration, the present exemplary embodiment canoptimally correct the parallel vibration according to the condition ofthe capture by the photographer.

In the first exemplary embodiment, the lens CPU 6808 calculates theparallel vibration correction target value using the average value ofthe rotational radiuses L that has been calculated before the start ofthe capture. In this regard, however, if the time period for calculatingthe rotational radius L is long as in the case where the time ofobserving the object is long, then the state of the vibration at thetime immediately before starting capture may become different from thestate of vibration at the start of the object observation.

In this regard, for example, the magnitude of the rotational radius Litself may vary due to the change in the manner of holding the camera.In addition, the relationship between the frequency and the rotationalradius L at the time immediately before starting capture may becomedifferent from that at the time of start of object observation.

Considering these cases, it is useful if an average value of therotational radiuses L is updated for each predetermined time periodinstead of using the average value of the rotational radiuses Lcalculated by the time immediately before the capture.

In the example illustrated in FIG. 27, the lens CPU 6808 compares thevelocity outputs V 2717 through 2723 with respect to each of angularvelocity outputs ω 2710 through 2716, each of which is detected during apredetermined period. Furthermore, the lens CPU 6808 calculates therotational radius L by calculating an angular velocity output ω and avelocity output V for each time period.

In the example illustrated in FIG. 28, the lens CPU 6808 compares thevelocity peak outputs V 2807 through 2809 with respect to each ofangular velocity peak outputs ω 2804 through 2806, each of which isdetected during a predetermined period. Furthermore, the lens CPU 6808calculates the rotational radius L by calculating an angular velocityoutput ω and a velocity output V for each time period. In addition, inthe first exemplary embodiment, the lens CPU 6808 calculates an averageof the rotational radiuses L in step S3213 (FIG. 32) and uses theaverage value for correcting the parallel vibration that may occurduring capture.

In the present exemplary embodiment, the lens CPU 6808 uses a movingaverage method as the method for calculating the average of therotational radiuses L. The present exemplary embodiment successivelyupdates the average value.

FIG. 40 is a timing chart that illustrates an example of operation inaccordance with the above-described configuration. In the exampleillustrated in FIG. 40, the elapsed time is shown on the horizontalaxis, while timing is shown on the vertical axis.

Referring to FIG. 40, after the photographer half-presses the releasebutton 6804 a at timing 4001 (the switch S1 is in an “on” state), thenthe lens CPU 6808 starts the detection of the rotational radius L attiming 4003. Rotational radiuses L01 through L22 each indicate arotational radius L to be calculated for each time period.

In the first exemplary embodiment, the lens CPU 6808 calculates therotational radius L to be used for correcting the parallel vibration byaveraging all of the rotational radiuses L01 through L19, which aredetected during the time period before the photographer fully pressesthe release button 6804 a (the switch S2 is in an “on” state) at timing4002. In this regard, the present exemplary embodiment updates therotational radius L for each predetermined time period.

As illustrated in FIG. 40, when the rotational radiuses L01 through L10are calculated, then the lens CPU 6808 calculates an average rotationalradius L 0110 of the rotational radiuses L01 through L10. Then, the lensCPU 6808 calculates a moving average of rotational radius L every time arotational radius L is calculated. Thus, the present exemplaryembodiment updates the rotational radius for correcting the parallelvibration.

In the example illustrated in FIG. 40, the capture starts when therotational radius L19 is calculated. Accordingly, the lens CPU 6808corrects the parallel vibration using the moving average value L1019 atthe time the rotational radius L19 is calculated. More specifically, thelens CPU 6808 continues updating the moving average value of therotational radius L. When the capture starts, the lens CPU 6808 correctsthe parallel vibration using a latest moving average value when thecapture starts.

As described above with reference to FIG. 39, with respect to therotational radius L 1019, the lens CPU 6808 calculates two types ofrotational radiuses L, namely, the rotational radius L at 5 Hz and therotational radius L at 1 Hz. The lens CPU 6808 determines whether toadjust the rotational radius L for each frequency according to thecomparison result.

By updating the rotational radius L in the above-described manner, thepresent exemplary embodiment can correct the parallel vibration withhigh accuracy using the rotational radius L suitable for the currentcapture condition. If the method using the area described above withreference to FIG. 29 is employed, it is useful to employ the followingconfiguration. More specifically, in this case, the lens CPU 6808continues updating the rotational radius L that has been calculated foreach period by the moving average method illustrated in FIG. 40. Whenthe capture starts, the lens CPU 6808 corrects the parallel vibrationusing the latest moving average value.

If the rotational radius L is calculated using the moving averagemethod, the time period for averaging becomes shorter than that in thefirst exemplary embodiment. Accordingly, if the rotational radius L isnot calculated during vibration from the driving of the camera or thelens, the vibration cannot be appropriately corrected in the capturestarting immediately after the vibration due to driving of the camera orthe lens has occurred.

In this regard, in the present exemplary embodiment, the rotationalradius L is calculated when the lens is driven for AF. However, asdescribed above in the first exemplary embodiment, if the output of theACC 101 p or the ACC 101 y is saturated due to the vibration from thedriving, the rotational radius L cannot be accurately calculated.

In the present exemplary embodiment, the sensitivity of the ACC 101 p isreduced to a level at which no saturation occurs. Then, the lens CPU6808 detects the vibration acceleration in this state and compares thedetected vibration acceleration with the angular velocity output.

However, if the acceleration sensitivity is lowered, the accelerationdetection output may be degraded. In this regard, the present exemplaryembodiment reduces the sensitivity of the ACC 101 p only at the timingat which vibration from the driving occurs.

In the present exemplary embodiment, in a normal operation state, thevibration acceleration can be detected with high accuracy. The lens CPU6808 lowers the acceleration sensitivity only during a short time periodin which vibration from driving occurs. Thus, while the accuracy ofdetecting the vibration acceleration during the driving vibrationoccurring time period may degrade, the degradation of the accuracy canbe reduced by the moving average of the rotational radiuses L before andafter the driving vibration.

FIG. 41 is a block diagram illustrating additional blocks forcontrolling the sensitivity of the ACC 101 p in the configurationillustrated in FIG. 39. In the example illustrated in FIG. 41, the ACC101 p includes a mechanical portion 101 pc, which includes micro electromechanical systems (MEMS), a first-stage amplifier 101 pd, and aprocessing circuit 101 pe.

The gain of the first-stage amplifier 101 pd is variable when a signalis input from a gain change determination unit 4101. The output of theACC 101 p is input to the HPF integration filter 305 via a windowcomparator 4103. The output of the HPF integration filter 305 is inputto the ACC BPF 1 unit 3902 and the ACC BPF 2 unit 3904 via a gaincorrection unit 4104.

The output of the window comparator 4103 is also input to the gainchange determination unit 4101. When the output of the ACC 101 p isoutside the level of a first area, the window comparator 4103 outputs again reducing signal. After receiving the gain reducing signal, the gainchange determination unit 4101 reduces the gain of the first-stageamplifier 101 pd. The first area is set at a level of about 80% of thesaturation level of the output of the ACC.

If the output of the ACC is within the level of a second range for apredetermined length of time (e.g., 0.1 second), the window comparator4103 outputs a gain returning signal. After receiving the gain returningsignal, the gain change determination unit 4101 returns the gain of thefirst-stage amplifier 101 pd to its original value. The second range isset to the level one-third of the first area because the gain of thefirst-stage amplifier 101 pd is reduced to one-third after the gain ischanged and thus the lens CPU 6808 uses the same level as the level ofthe first area in this state.

A rotational radius L calculation non-completion signal from theadjustment availability determination unit 3907 is input to a gainreturn inhibition unit 4102. During this period, the gain returninhibition unit 4102 outputs a gain return inhibition signal to the gainchange determination unit 4101.

Accordingly, during the time period in which the comparison units 3905and 3906 calculate the rotational radius L, the gain of the first-stageamplifier 101 pd is not returned to its original value in order toprevent possible degradation of the accuracy of detecting the rotationalradius L that may occur when the gain of the first-stage amplifier 101pd is changed during the calculation of the rotational radius L.

The gain correction unit 4104 returns the gain to the original value ifthe gain of the first-stage amplifier 101 pd is small. In the presentexemplary embodiment, the gain correction unit 4104 is provided at alater stage of the HPF integration filter 305.

When vibration from driving occurs, a high-frequency noise is superposedon the output of the ACC 101 p. Accordingly, the output of the ACC 101 pmay be saturated in this case. However, because the output of the HPFintegration filter 305 is calculated by integrating the ACC output, thehigh-frequency signal can be sufficiently attenuated.

Accordingly, the output is not saturated even if the gain of the outputof units provided downstream of the HPF integration filter 305 isincreased. More specifically, the present exemplary embodiment correctsthe error of the rotational radius L occurring due to the change of thegain of the first-stage amplifier 101 pd by preventing the saturation ofthe output of the ACC 101 p by reducing the gain of the first-stageamplifier 101 pd and thus correcting the gain after integrating theoutput of the ACC 101 p.

FIG. 42 illustrates the above-described configuration with an outputwaveform of the ACC according to the present exemplary embodiment. Inthe example illustrated in FIG. 42, the elapsed time is shown on thehorizontal axis, while the ACC output is shown on the vertical axis.

Referring to FIG. 42, waveforms 4201 and 4203 indicate outputs of theACC 101 p (in periods 4204 and 4206) when the gain of the first-stageamplifier 101 pd is normal. A waveform 4202 indicates the output of theACC 101 p (in a period 4205) when the gain of the first-stage amplifier101 pd is reduced to one-third.

In the example illustrated in FIG. 42, with respect to the waveform4201, when an impact indicated by an arrow 4209 is input, the output ofthe impact has exceeded a determination level (first area) 4207.Accordingly, the window comparator 4103 outputs a gain reducing signalto reduce the gain of the first-stage amplifier 101 pd and acquire awaveform 4202.

When another impact, which is indicated by an arrow 4210, is input, thewaveform 4202 does not exceed a determination level 4208 (second range).At this time, the gain of the first-stage amplifier 101 pd has beenreduced to one-third. Accordingly, the lens CPU 6808 sets thedetermination level, which is the second range, at the level equivalentto one-third of the first area determination level to execute thedetermination at the same level.

As described above, the lens CPU 6808 executes control for returning thegain of the first-stage amplifier 101 pd to its original value after apredetermined time period (a verification time 4211) has elapsed afterthe waveform 4202 has fallen within the second range determination level4208.

However, with respect to the verification time period 4211, theseparation between time periods for calculating the rotational radius Lis considered as well as timing a predetermined time period (e.g., 0.1second). More specifically, if a result of calculation of the rotationalradius L is acquired after 0.04 seconds from the predetermined timeperiod (e.g., 0.1 second), then the verification time period 4211becomes 0.14 seconds. The lens CPU 6808 calculates a next rotationalradius L after returning the gain of the first-stage amplifier 101 pd toits original value.

FIG. 43 is a flow chart illustrating an exemplary operation for changing(switching) the gain of the ACC 101 p and the gain of the first-stageamplifier 101 pd. The flow starts when the ACC is activated and the flowis repeatedly executed as a loop until the operation of the ACC isstopped.

Referring to FIG. 43, in step S4301, the window comparator 4103determines whether the ACC output is outside the first area 4207. If itis determined that the ACC output is outside the first area 4207 (YES instep S4301), then the processing advances to step S4302. On the otherhand, if it is determined that that the ACC output is not outside thefirst area 4207 (NO in step S4301), then the lens CPU 6808 repeats theprocessing in step S4301 and waits until the ACC output becomes outsidethe first area 4207.

In step S4302, the gain change determination unit 4101 reduces the gainof the first-stage amplifier 101 pd to one-third of the current level.Furthermore, the gain correction unit 4104 corrects the gain bymultiplying the acceleration output three-fold.

In step S4303, the window comparator 4103 determines whether the ACCoutput has returned to the level within the second range determinationlevel 4208. If it is determined that the ACC output has returned to thelevel within the second range determination level 4208 (YES in stepS4303), then the processing advances to step S4304. On the other hand,if it is determined that the ACC output has not returned to the levelwithin the second range determination level 4208 (NO in step S4303),then the processing repeats the processing in step S4303 to wait untilthe gain of the first-stage amplifier 101 pd returns to the level withinthe second range determination level 4208.

In step S4304, the lens CPU 6808 waits for a predetermined length oftime (e.g., 0.1 second). In step S4305, the lens CPU 6808 waits untilthe calculation of rotational radius L in the current time period iscompleted.

In step S4306, the gain change determination unit 4101 returns the gainof the first-stage amplifier 101 pd to its original value. Furthermore,the gain correction unit 4104 returns the acceleration output afterintegration to one power. Then, the processing returns to step S4301.

As described above, the lens CPU 6808 reduces the gain before the outputof the ACC 101 p becomes saturated. Thus, the present exemplaryembodiment prevents saturation of the ACC 101 p and corrects theshortage of gain with the acceleration output after integration.Accordingly, the saturation of correction value can be prevented.

FIG. 44 is a flow chart illustrating an exemplary operation of maincomponents according to the second exemplary embodiment of the presentinvention. The processing in the flow chart of FIG. 44 is roughlyequivalent to that illustrated in FIG. 32 in the first exemplaryembodiment.

The processing in the flow chart of FIG. 44 is different from thatillustrated in FIG. 32 in the following points. More specifically, inthe present exemplary embodiment, the lens CPU 6808 calculates themoving average of the calculated rotational radiuses as well asdetecting the rotational radius in steps S4401 and S4403 instead ofexecuting the calculation of the rotational radius L in steps S3206 andS3228. In addition, in the present exemplary embodiment, the suspensionof detection of the rotational radius in step S3230 is omitted. This isbecause after the gain of the first-stage amplifier 101 pd of the ACC101 p has been reduced, the saturation of the ACC output, which mayotherwise occur due to vibration from the driving of lens for focusing,does not occur and thus the rotational radius L can be calculated duringthe time period.

FIG. 45 is a timing chart according to the present exemplary embodiment.The timing chart illustrated in FIG. 45 is roughly equivalent to thatillustrated in FIG. 30 in the first exemplary embodiment. The timingchart illustrated in FIG. 45 is roughly similar to that illustrated inFIG. 30 except that in the exemplary timing chart illustrated in FIG.45, a rotational radius detection timing 4501 is set instead of therotational radius detection timing 3009.

At the rotational radius detection timing 4501, the lens CPU 6808calculates the rotational radius based on the outputs from the gyro andthe ACC. A “Hi” state indicates that the rotational radius is calculatedwhile a “Lo” state indicates that the calculation of the rotationalradius is suspended. The rotational radius detection timing 4501 isdifferent from the rotational radius detection timing 3009 in the pointthat in the present exemplary embodiment, the lens CPU 6808 calculatesthe rotational radius L even during the time period from time t3 to timet5.

Returning to FIG. 44, the processing illustrated in the flow chart ofFIG. 44 is different from that illustrated in FIG. 32 in the followingpoint. More specifically, in the present exemplary embodiment, in stepS4402, the lens CPU 6808 suspends the detection of the rotational radiusand uses a latest updated rotational radius to correct the parallelvibration instead of suspending the detection of the rotational radiusand averaging the rotational radius in step S3213. The other processingis similar to that described above in FIG. 32. Accordingly, thedescription thereof will not be repeated here.

As can be seen from the flow illustrated in FIG. 44, the lens CPU 6808suspends the detection of the rotational radius L while the shutter, thequick return mirror, or the diaphragm is driven as the lens CPU 6808does in the first exemplary embodiment. Note here the detection of therotational radius L may be executed in a time period for driving theshutter, the quick return mirror, or the diaphragm.

However, if the detection of the rotational radius L is continued duringthe above-described time period, the camera is subjected to extremelygreat vibration occurring due to the driving. In this case, it isnecessary to reduce the gain of the first-stage amplifier 101 pd of theACC 101 p is reduced to prevent the saturation of the ACC output thatmay occur due to the driving vibration. Accordingly, in this case, theACC output may become instable due to the great reduction of the gain.Accordingly, the accuracy of detecting the rotational radius calculatedduring the above-described time period becomes extremely low. Therefore,the lens CPU 6808 suspends the detection of the rotational radius L.

As is described above with reference to FIG. 38, the lens CPU 6808corrects the rotational radius L based on the information about theinstallation location of the ACC 101 p and the displacement of theprincipal point of the imaging optical system. However, the influencefrom the parallel vibration can be reduced or suppressed if the ACC 101p is disposed at the same position as the principal point of the imagingoptical system when the greatest imaging magnification is set and if thecurrent imaging magnification is below the greatest imagingmagnification.

Accordingly, in this case, the parallel vibration can be corrected witha sufficiently high accuracy without correcting the rotational radius L.Therefore, the entire system can be simplified.

In an example illustrated in FIG. 46, the ACC 101 p is disposed at thesame position as a principal point A 4602 of the imaging optical systemin a state in which the imaging magnification is highest within thecapacity of the photographic lens (at a closest object distance position4601). Accordingly, the rotational radius L 1101 p, which is calculatedbased on the output of the ACC 101 p and the output of the gyro 6807 p,is equal to the rotational radius from the rotational center to theprincipal point of the imaging optical system. Thus, the parallelvibration can be corrected with high accuracy with this configuration.An amount of vibration 4603 at the principal point A 4602 of the imagingoptical system is equal to the amount of vibration 4603 at theinstallation location of the ACC 101 p.

FIG. 47 illustrates a case where an object 4701 is distant from theimaging optical system. In this case, a principal point B 4702 of theimaging optical system when focusing on the object 4701 is displacedfrom the installation location 4602 of the ACC 101 p.

An amount of vibration 4703 at the principal point B 4702 of the imagingoptical system is different from the vibration amount 4603 at theinstallation location of the ACC 101 p. However, in this case, theimaging magnification is low. Accordingly, the influence from theparallel vibration that may cause image degradation is small.Accordingly, the parallel vibration can be corrected with a tolerablyhigh accuracy without strictly setting a rotational radius L.

It is significant to dispose the ACC 101 p at the same position as theprincipal point of the lens when the imaging magnification of theimaging optical system becomes greatest. If the ACC 101 p can bedisposed at the same position as the principal point of the lens, thecalculation can be more simplified compared with the calculation in theabove-described first exemplary embodiment.

It is not always necessary to dispose the ACC 101 p on the principalpoint of the imaging optical system. That is, if the installationlocation of the ACC 101 p is deviated from the principal point of theimaging optical system, the rotational radius correction unit 309 c(FIG. 38) can correct the deviation.

That is, instead of simplifying the configuration of the system byomitting the deviation amount calculation unit 309 d (FIG. 38), thedeviation between the principal point of the imaging optical system andthe ACC when the maximum capture magnification is used is set as a fixedvalue as the correction value for correcting the rotational radius L.

If the method described above with reference to FIG. 38 is used, theflexibility in determining the installation location of the ACC becomesvery high. As described above with reference to FIG. 36, because therotational center exists on the back side of the camera, the detectionaccuracy increases since the more distant the installation location ofthe ACC is from the rotational center, the greater the accelerationarising due to vibration becomes. Accordingly, it is useful to disposethe ACC at a position of the capture lens 6801 closest to the object.

In the present exemplary embodiment, the parallel vibration is correctedby correcting the output of the gyro based on a latest updated value ofthe correction values of the output of the gyro of the output correctionunit 309, which is updated before the capture starts. Accordingly, theparallel vibration can be corrected with high accuracy.

More specifically, the comparison units 3905 and 3906 calculate therotational radius (correction value) at intervals of a predeterminedperiod (periods L01 through L10 (FIG. 40)) before the capture starts andupdate the average of the rotational radius L. Furthermore, thecomparison units 3905 and 3906 output the updated rotational radius atthe start of capture to the output correction unit 309 in step S4402(FIG. 44).

To paraphrase this, the comparison units 3905 and 3906 update theaverage value of the rotational radiuses, which is calculated in eachperiod before the start of capture. Furthermore, the comparison units3905 and 3906 output the average value of the rotational radius updatedat the start of capture to the output correction unit 309. Thus, theparallel vibration is corrected. It is also useful if a value acquiredby updating the average value calculated by the moving average method ineach period is used as the rotational radius.

A third exemplary embodiment of the present invention is describedbelow. FIG. 48 illustrates an exemplary configuration of the imagestabilization control apparatus included in a single-lens reflex cameraaccording to the present exemplary embodiment. The appearance of thecamera is similar to those in the first and second exemplary embodimentsillustrated in FIGS. 1 and 2.

The present exemplary embodiment is different from the above-describedfirst and second exemplary embodiments in the following points.

-   -   The gain of the first-stage amplifier 101 pd of the ACC 101 p is        changed based on a camera actuator driving timing signal instead        of a result of the determination by the window comparator 4103        described above with reference to FIG. 41.    -   The correction of the parallel vibration is executed by using an        optimum rotational radius L among a plurality of frequency        levels instead of optimizing the rotational radius L with        respect to each frequency by adjusting the gain of the integral        signal of the gyro 6807 p described above with reference to FIG.        3.

Accordingly, the configuration of the present exemplary embodiment (FIG.48) is different from the configuration described above with referenceto FIG. 41 in the following points.

1) The configuration according to the present exemplary embodimentadditionally includes a lens driving instruction unit 4801, a lensdriving unit 4802, and a lens driving mechanism 4803, which are notillustrated in the above-described block diagrams.

2) A gyro BPF 3 unit 4804, an ACC BPF 3 unit 4805, a comparison unit4806, and a rotational radius selection unit 4807 are included in theconfiguration of the present exemplary embodiment.

3) The HPF integration filter 310, the gain adjustment unit 311, and theinput switching unit 309 are omitted in the configuration of the presentexemplary embodiment.

In this regard, to begin with, the switching (changing) of the gain ofthe ACC 101 p according to the present exemplary embodiment is describedin detail below. In the above-described second exemplary embodiment, thegain of the first-stage amplifier 101 pd is changed according to themagnitude of the output of the ACC itself. In the present exemplaryembodiment, the gain of the first-stage amplifier 101 pd is changedaccording to a lens driving instruction signal for focusing.

Referring to FIG. 48, information about operation of the release button6804 a and a lens driving signal are input to the lens CPU 6808. Afterreceiving the information and the signal, the lens driving instructionunit 4801 drives the lens (focusing lens) for focusing. Morespecifically, the lens driving instruction unit 4801 outputs a lensdriving instruction signal to the lens driving unit 4802. The lensdriving unit 4802 drives the lens driving mechanism 4803 based on thelens driving instruction signal to move the lens for focusing.

The lens driving instruction signal from the lens driving instructionunit 4801 is also input to the gain change determination unit 4101. Thegain change determination unit 4101 changes the gain of the first-stageamplifier 101 pd based on the lens driving instruction signal. Morespecifically, when the lens driving instruction is input, the gainchange determination unit 4101 reduces the gain of the first-stageamplifier 101 pd for an instructed time period. Furthermore, the gainchange determination unit 4101 increases the gain of the gain correctionunit 4104 during the time period in which the gain of the first-stageamplifier 101 pd is reduced. Thus, the gain change determination unit4101 prevents variation of the entire gain.

FIG. 49 illustrates the above-described operation with a waveform of theACC 101 p. In the example illustrated in FIG. 49, the elapsed time isshown on the horizontal axis. The ACC output is shown on the verticalaxis.

The waveforms 4201 and 4203 indicate the outputs of the ACC 101 p duringthe time periods 4204 and 4206 when the gain of the first-stageamplifier 101 pd is normal. The waveform 4202 indicates the output ofthe ACC 101 p in the time period 4205 when the gain of the first-stageamplifier is reduced to one-third of the original level.

With respect to the waveform 4201, the gain of the first-stage amplifier101 pd is reduced at a timing of starting an instruction for driving thelens from the lens driving instruction unit 4801, which is indicated byan arrow 4901 in FIG. 49. Thus, the waveform 4202 is acquired.

Then, at the timing of suspension of the lens driving instruction, whichis indicated by an arrow 4902, the occurrence of vibration from drivingof the lens ends. The gain of the first-stage amplifier 101 pd can bereturned to its original value at this timing. However, in the presentexemplary embodiment, the gain of the first-stage amplifier 101 pd isreturned to its original value after waiting for a separation of timingof calculating a rotational radius L, which is indicated by an arrow4903. The gain return inhibition unit 4102 operates as described abovewith reference to FIG. 42.

The gain return inhibition unit 4102 inhibits the gain changedetermination unit 4101 from returning the gain to its original valuebefore a rotational radius selection signal is input from the rotationalradius selection unit 4807. The lens CPU 6808 calculates a nextrotational radius L after returning the gain of the first-stageamplifier 101 pd to the original value.

If the lens driving timing is utilized as described above, it isbeneficial to set a long time period of reducing the gain consideringthe displacement between the driving instruction timing and the timingof occurrence of vibration from the actual driving. In this case, thetiming for returning the gain to its original value can be securelyacquired although it is necessary to reduce the gain at a drivinginstruction timing before the lens is actually driven.

In the above-described second exemplary embodiment, the lens CPU 6808returns the gain to its original value if the output detected by the ACC101 p is reduced for a predetermined time period so as not to return thegain to its original value when an impact is momentarily lost during atime period in which the camera is subjected to continuous impacts.

In the present exemplary embodiment, the lens CPU 6808 detects a drivinginstruction timing. Accordingly, because a driving end timing is input,the lens CPU 6808 can recognize that a great vibration is not applied tothe camera after the driving end timing is input. Therefore, it is notnecessary in the present exemplary embodiment to monitor the ACC outputfor a predetermined time period and return the gain to its originalvalue based on a result of the monitoring of the ACC output as in thesecond exemplary embodiment.

Furthermore, a method for correcting the parallel vibration using anoptimum rotational radius L among the rotational radiuses L for aplurality of frequency levels is described in detail below.

In the present exemplary embodiment, three pairs of BPFs are used tocalculate the rotational radius L as illustrated in FIG. 48. The gyroBPF 1 unit 3901 extracts an angular velocity signal (the output of theHPF phase adjustment unit 304) at 2 Hz. The ACC BPF 1 unit 3902 extractsan ACC signal (the output of the gain correction unit 4104) at 2 Hz. Thecomparison unit 3905 compares the angular velocity signal and the ACCsignal to calculate a rotational radius L as in the first exemplaryembodiment.

Similarly, the gyro BPF 2 unit 3903 extracts an angular velocity signal(the output of the HPF phase adjustment unit 304) at 5 Hz, while the ACCBPF 2 unit 3904 extracts an ACC signal (the output of the gaincorrection unit 4104) at 5 Hz. The comparison unit 3906 compares theangular velocity signal and the ACC signal to calculate a rotationalradius L as in the first exemplary embodiment.

The gyro BPF 3 unit 4804 extracts an angular velocity signal (the outputof the HPF phase adjustment unit 304) at 8 Hz, while the ACC BPF 3 unit4805 extracts an ACC signal (the output of the gain correction unit4104) at 8 Hz. The comparison unit 4806 compares the angular velocitysignal and the ACC signal to calculate a rotational radius L as in thefirst exemplary embodiment.

The rotational radius selection unit 4807 selects an optimum rotationalradius among the rotational radiuses L calculated by the comparisonunits 3905, 3906, and 4806 and outputs the selected optimum rotationalradius L to the output correction unit 309. Accordingly, the presentexemplary embodiment can correct the parallel vibration using therotational radius L at the frequency selected by the rotational radiusselection unit 4807 (the output of the rotational radius selection unit4807) among the extraction frequency levels (2 Hz, 5 Hz, or 8 Hz).

In the present exemplary embodiment, the gain adjustment unit 311illustrated in FIG. 3 is not used. Accordingly, the HPF integrationfilter 310 for correcting the phase displacement of the gain adjustmentunit 311 is not necessary in the present exemplary embodiment.Therefore, the present exemplary embodiment calculates the angularvibration correction target value and the parallel vibration correctiontarget value based on the output of the HPF integration filter 301.

A method for calculating an optimum rotational radius L with therotational radius selection unit 4807 is described in detail below.

FIG. 50 illustrates exemplary waveforms of vibration in the imagestabilization control apparatus according to the present exemplaryembodiment. Referring to FIG. 50, a waveform 5001 indicates an output ofthe ACC BPF 1 unit 3902. The waveform 5008 is a signal waveform acquiredby multiplying the output of the gyro BPF 1 unit 3901 by a rotationalradius calculated by the comparison unit 3905. That is, the waveform5008 indicates the velocity calculated based on the output of the gyro6807 p. The dimension of the waveform 5008 is similar to that of thewaveform 5001. The positional relationship between the waveforms 5001and 5008 may be offset from each other.

If the rotational center is fixed at one position, the waveforms 5001and 5008 positionally match. However, if a plurality of rotationalcenters exists and the ACC 101 p has detected a combined vibration fromthe plurality of rotational centers, then the phase against the angularvelocity signal may vary according to the magnitude of the vibration ateach rotational center at a specific moment. Accordingly, in this case,the positional offset between the waveforms 5001 and 5008 may occur.

In this regard, if the parallel vibration is corrected using arotational radius L at a frequency at which the waveform of the outputof the ACC BPF 1 unit 3902 and the waveform of the output acquired bymultiplying the output of the gyro BPF 1 unit 3901 by the rotationalradius L match each other and also at which the phase of the output ofthe ACC BPF 1 unit 3902 and the phase of the output calculated bymultiplying the output of the gyro BPF 1 unit 3901 by the rotationalradius L match each other, then the accuracy of correcting the parallelvibration can become very high.

In this regard, the rotational radius selection unit 4807 calculates awaveform 5009, which is a difference between the waveforms 5001 and5008, in order to determine the matching status (matching degree)between the two waveforms 5001 and 5008. The rotational radius selectionunit 4807 periodically executes sampling on the waveforms 5001 and 5009and compares the result of the sampling.

In the example illustrated in FIG. 50, arrows 5002 through 5004 eachindicate a sampling period. Arrows 5005 through 5007 and 5010 through5012 each indicate a maximum amplitude (difference between maximum andminimum values) of the waveforms 5001 and 5009 during the samplingperiods.

As the sampling period, the present exemplary embodiment sets a periodof the extraction frequency. In this regard, if the extraction frequencyis set at 2 Hz, the sampling period is 0.5 seconds.

The lens CPU 6808 averages the maximum amplitudes of the waveforms 5001and 5009 for each period calculated, in the above-described manner, toprevent degradation of the accuracy of determination that may occur dueto a sudden change, if any, of the maximum amplitude.

In synchronization with the start of the detection of the rotationalradius L, the rotational radius selection unit 4807 starts calculatingthe maximum amplitudes of the waveforms 5001 and 5009 and calculates theaverages thereof until immediately before the capture starts.Furthermore, the lens CPU 6808 calculates the ratio of the averagevalues to calculate a matching status determination value, which is tobe used for determining the degree of matching of the waveforms 5001 and5008.

The matching degree between the waveforms 5001 and 5008 becomes higheras the matching status determination value decreases. With respect tothe average of the maximum amplitudes of the waveforms 5001 and 5009, itis also useful if the method for updating moving averages for eachpredetermined time period described above with reference to FIG. 2 isused instead of using the average of the maximum amplitudes during thetime period from the start of detection of the rotational radius to thestart of capture. In this case, the lens CPU 6808 can calculate thematching status determination value by using the latest updated value atthe time period immediately before the start of capture.

FIG. 51 illustrates exemplary waveforms of vibration in the imagestabilization control apparatus according to the present exemplaryembodiment. Referring to FIG. 51, a waveform 5101 indicates the outputof the ACC BPF 2 unit 3904 the ACC BPF 2 unit 3904. A waveform 5108 is asignal waveform acquired by multiplying the output of the ACC BPF 2 unit3904 by the rotational radius L calculated by the comparison unit 3906.

In this regard, the rotational radius selection unit 4807 calculates awaveform 5109, which is a difference between the waveforms 5101 and5108, in order to determine the matching status (matching degree)between the two waveforms 5101 and 5108. The rotational radius selectionunit 4807 periodically executes sampling on the waveforms 5101 and 5109and compares the result of the sampling.

In the example illustrated in FIG. 51, arrows 5102 through 5104 eachindicate a sampling period. Arrows 5105 through 5107 and 5110 through5112 each indicate a maximum amplitude (difference between maximum andminimum values) of the waveforms 5101 and 5109 during the samplingperiods.

With respect to the sampling period, the same sampling period as thatdescribed above with reference to FIG. 50 is used. Accordingly, the samecondition for calculating the matching status determination valuecalculated by the method described above with reference to FIG. 50 canbe used in the method described with reference to FIG. 51. The lens CPU6808 averages the maximum amplitudes of the waveforms 5101 and 5109 foreach frequency calculated in the above-described manner.

In synchronization with the start of the detection of the rotationalradius L, the rotational radius selection unit 4807 starts calculatingthe maximum amplitudes of the waveforms 5101 and 5109 and calculates theaverages thereof until immediately before the capture starts.Furthermore, the lens CPU 6808 calculates the ratio of the averagevalues to calculate a matching status determination value, which is tobe used for determining the degree of matching of the waveforms 5101 and5108.

FIG. 52 illustrates exemplary waveforms of vibration in the imagestabilization control apparatus according to the present exemplaryembodiment. Referring to FIG. 52, a waveform 5201 indicates an output ofthe ACC BPF 3 unit 4805. A waveform 5208 is a signal waveform calculatedby multiplying the output of the gyro BPF 3 unit 4804 by the rotationalradius L calculated by the comparison unit 4806.

In this regard, the rotational radius selection unit 4807 calculates awaveform 5209, which is a difference between the waveforms 5201 and5208, in order to determine the matching status (matching degree)between the two waveforms 5201 and 5208. The rotational radius selectionunit 4807 periodically executes sampling on the waveforms 5201 and 5209and compares the result of the sampling.

In the example illustrated in FIG. 52, arrows 5202 through 5204 eachindicate a sampling period. Arrows 5205 through 5207 and 5210 through5212 each indicate a maximum amplitude (difference between maximum andminimum values) of the waveforms 5201 and 5209 during the samplingperiods.

With respect to the sampling period, the same sampling period as thatdescribed above with reference to FIG. 50 is used. Accordingly, the samecondition for calculating the matching status determination valuecalculated by the method described above with reference to FIG. 50 canbe used in the method described with reference to FIG. 52. The lens CPU6808 averages the maximum amplitudes of the waveforms 5201 and 5209 foreach frequency calculated in the above-described manner.

In synchronization with the start of the detection of the rotationalradius L, the rotational radius selection unit 4807 starts calculatingthe maximum amplitudes of the waveforms 5201 and 5209 and calculates theaverages thereof until immediately before the capture starts.Furthermore, the lens CPU 6808 calculates the ratio of the averagevalues to calculate a matching status determination value, which is tobe used for determining the degree of matching of the waveforms 5201 and5208.

As described above, the rotational radius selection unit 4807 calculatesthe matching status determination value at each frequency level of 2 Hz,5 Hz, and 8 Hz. Furthermore, the rotational radius selection unit 4807outputs a rotational radius L at a frequency at which the matchingstatus determination value becomes lowest (at which the matching degreeof the waveforms becomes highest) to the output correction unit 309.

The output correction unit 309 calculates a parallel vibrationcorrection target value by multiplying the output (vibration angle) ofthe HPF integration filter 301 of the gyro 6807 p by the inputrotational radius L and the imaging magnification, which is calculatedbased on the and the zoom and focus information 302.

The driving unit 6809 drives the vibration correction unit 6806 based onthe angular vibration correction target value from the sensitivityadjustment unit 303 during the time period in which the release button6804 a has been half-pressed to correct the angular vibration.

When the release button 6804 a is fully pressed (during the exposuretime period), the driving unit 6809 drives the vibration correction unit6806 based on the angular vibration correction target value and theparallel vibration correction target value from the output correctionunit 309.

With the above-described configuration, the present exemplary embodimentcan calculate a rotational radius L having the highest effect ofcorrecting the parallel vibration of all calculated rotational radiusesL. Accordingly, the present exemplary embodiment can correct theparallel vibration with high accuracy.

In the example illustrated in FIG. 48, a plurality of BPFs is used.However, the present exemplary embodiment is not limited to this. Forexample, it is also useful if Fourier transform is used to calculate therotational radius L at each frequency and select an optimum rotationalradius L at an appropriate frequency among the frequency levels, asdescribed above with reference to FIG. 26.

In this case, the lens CPU 6808 can calculate the matching statusdetermination value according to the difference between the velocity anda value calculated by multiplying the angular velocity by the rotationalradius L as described above with reference to FIGS. 50 through 52.Alternatively, it is also useful if the lens CPU 6808 selects arotational radius L at a frequency at which the offset against the phaseof the velocity (angular velocity×rotational radius) at each frequencycalculated by Fourier transform is smallest of all rotational radiusesL.

FIG. 53 illustrates an exemplary configuration employed in this caseaccording to the present exemplary embodiment.

The configuration illustrated in FIG. 53 is different from theconfiguration illustrated in FIG. 48 in the following point. That is,the configuration illustrated in FIG. 53 includes a gyro Fouriertransform 1 unit 5301, an ACC Fourier transform 1 unit 5302, a gyroFourier transform 2 unit 5303, an ACC Fourier transform 2 unit 5304, agyro Fourier transform 3 unit 5305, and an ACC Fourier transform 3 unit5306 instead of components illustrated in FIG. 48, namely, the gyro BPF1 unit 3901, the ACC BPF 1 unit 3902, the gyro BPF 2 unit 3903, the ACCBPF 2 unit 3904, the gyro BPF 3 unit 4804, and the ACC BPF 3 unit 4805.

The angular velocity and the spectrum of the velocity at each frequencycalculated by each Fourier transform unit can be calculated by theabove-described expressions (9) and (10). The rotational radiusselection unit 4807 calculates the phase of the velocity and the phaseof the angular velocity at each frequency by using the followingexpressions (17) and (18):

$\begin{matrix}{\phi_{V_{F}} = \frac{\sum\limits_{t = 0}^{\frac{n}{f}}\; {{G(t)}\sin \; 2\pi \; f}}{\sum\limits_{t = 0}^{\frac{n}{f}}\; {{G(t)}\cos \; 2\pi \; f}}} & (17) \\{\phi_{\omega_{F}} = {\frac{\sum\limits_{t = 0}^{\frac{n}{f}}\; {{H(t)}\sin \; 2\pi \; f}}{\sum\limits_{t = 0}^{\frac{n}{f}}\; {{H(t)}\cos \; 2\pi \; f}}.}} & (18)\end{matrix}$

In an ideal case where only one rotational center exists, the phase ofthe velocity calculated by the expression (17) and the phase of theangular velocity calculated by the expression (18) should match eachother. However, if a plurality of rotational centers exists and the ACChas detected a combined vibration from the rotational center, then thephase against the angular velocity signal may vary due to the magnitudeof each rotational center at a specific time.

In the present exemplary embodiment, the rotational radius selectionunit 4807 calculates the difference between the phases resulting fromthe calculation by the expressions (17) and (18) (the expressions forcalculating the velocity and the angular velocity) by using theexpressions (17) and (18). Furthermore, the rotational radius selectionunit 4807 outputs the rotational radius L at a frequency at which thedifference between the phases resulting from the calculation by theexpressions (17) and (18) is smallest to the output correction unit 309.

The output correction unit 309 calculates a parallel vibrationcorrection target value by multiplying the output (vibration angle) ofthe HPF integration filter 301 of the gyro 6807 p by the inputrotational radius L and the imaging magnification, which is calculatedbased on the zoom and focus information 302.

The driving unit 6809 drives the vibration correction unit 6806 based onthe angular vibration correction target value from the sensitivityadjustment unit 303 during the time period in which the release button6804 a has been half-pressed to correct the angular vibration.

When the release button 6804 a is fully pressed (during the exposuretime period), the driving unit 6809 drives the vibration correction unit6806 based on the angular vibration correction target value and theparallel vibration correction target value from the output correctionunit 309.

With the above-described configuration, the present exemplary embodimentcan calculate a rotational radius L having the highest effect ofcorrecting the parallel vibration of all calculated rotational radiusesL. Accordingly, the present exemplary embodiment can correct theparallel vibration with high accuracy.

A fourth exemplary embodiment of the present invention is describedbelow. FIG. 54 illustrates an exemplary configuration of the imagestabilization control apparatus included in a single-lens reflex cameraaccording to the present exemplary embodiment.

The present exemplary embodiment is different from the above-describedthird exemplary embodiment in the following points.

-   -   The gain of the first-stage amplifier 101 pd of the ACC 101 p is        reduced based on a result of the determination by the window        comparator 4103 described above with reference to FIG. 41 but        whether to return the reduced gain to its original value is        switched based on a camera actuator driving timing signal.    -   The rotational radius L is used as the average value of the        rotational radiuses L at a plurality of frequency levels.

Accordingly, the configuration of the present exemplary embodiment (FIG.54) is different from the configuration described above with referenceto FIG. 48 in the following points.

1) The configuration according to the present exemplary embodimentincludes the window comparator 4103.

2) The rotational radius averaging unit 5401 is included instead of therotational radius selection unit 4807.

To begin with, a method for changing the gain of the ACC 101 p isdescribed in detail below. In the above-described third exemplaryembodiment, the reduction and the returning of the gain of thefirst-stage amplifier 101 pd are executed based on a lens drivinginstruction signal for focusing. In this regard, in the presentexemplary embodiment, the lens CPU 6808 reduces the gain of thefirst-stage amplifier 101 pd according to the magnitude of the output ofthe ACC 101 p as in the second exemplary embodiment. Furthermore, in thepresent exemplary embodiment, the lens CPU 6808 returns the gain to itsoriginal value according to a lens driving instruction signal forfocusing as in the third exemplary embodiment.

FIG. 55 illustrates the above-described processing with an waveform ofthe ACC 101 p. In the example illustrated in FIG. 55, the elapsed timeis shown on the horizontal axis. The ACC output is shown on the verticalaxis.

The waveforms 4201 and 4203 indicate the outputs of the ACC 101 p duringthe time periods 4204 and 4206 when the gain of the first-stageamplifier 101 pd is normal. The waveform 4202 indicates the output ofthe ACC 101 p in the time period 4205 when the gain of the first-stageamplifier is reduced to one-third of the original level.

In the example illustrated in FIG. 55, with respect to the waveform4201, when an impact indicated by an arrow 4209 is input, the output ofthe impact has exceeded the determination level (first area) 4207.Accordingly, the window comparator 4103 outputs a gain reducing signalto reduce the gain of the first-stage amplifier 101 pd and acquire awaveform 4202.

Then, at timing of suspension of the lens driving instruction, which isindicated by an arrow 4902, the occurrence of vibration from driving ofthe lens ends. The gain of the first-stage amplifier 101 pd can bereturned to its original value at this timing. However, in the presentexemplary embodiment, the gain of the first-stage amplifier 101 pd isreturned to its original value after waiting for a separation of timingof calculating a rotational radius L, which is indicated by an arrow4903. The gain return inhibition unit 4102 operates as described abovewith reference to FIG. 42.

The gain return inhibition unit 4102 inhibits the gain changedetermination unit 4101 from returning the gain to its original valuebefore a rotational radius averaging signal is input from the rotationalradius averaging unit 5401. The lens CPU 6808 calculates a nextrotational radius L after returning the gain of the first-stageamplifier 101 pd to the original value.

By utilizing the ACC output in reducing the gain, the present exemplaryembodiment can reduce the gain of the first-stage amplifier 101 pd onlywhen it is useful.

With respect to the timing for returning the gain to its original value,the present exemplary embodiment utilizes a reliable timing at which noactuator is driven instead of determining whether the gain can bereturned to its original value by observing the waveform for apredetermined time period after the ACC output is reduced as describedabove in the second exemplary embodiment.

In the above-described second exemplary embodiment, the lens CPU 6808returns the gain to its original value if the output detected by the ACC101 p is reduced for a predetermined time period so as not to return thegain to its original value when an impact is momentarily lost during atime period in which the camera is subjected to continuous impacts.

In the present exemplary embodiment, the lens CPU 6808 detects a drivinginstruction timing. Accordingly, because a driving end timing is input,the lens CPU 6808 can recognize that a great vibration is no applied tothe camera after the driving end timing is input.

Now, a method for correcting the parallel vibration by calculating andusing an average value of rotational radiuses L at a plurality offrequency levels is described in detail below.

The present exemplary embodiment uses three pairs of BPFs in calculatingthe rotational radius L as described above with reference to FIG. 48.The rotational radius averaging unit 5401 calculates the average valueof the rotational radiuses L calculated by the comparison units 3905,3906, and 4806. Accordingly, the present exemplary embodiment correctsthe parallel vibration by using the rotational radius L averaged by therotational radius averaging unit 5401 at the extraction frequency levelsof 2 Hz, 5 Hz, and 8 Hz, for example.

The rotational radius averaging unit 5401 calculates the average of therotational radiuses L calculated by the comparison units 3905, 3906, and4806 for each of the sampling periods 5002 through 5004 illustrated inFIGS. 50 through 52. When the capture starts, the lens CPU 6808 furthercalculates an average of the average values of the rotational radiuses Lcalculated for each sampling period to correct the parallel vibration.

With respect to the averaging of the rotational radiuses L forcorrecting the parallel vibration, it is also useful if the movingaverage for each predetermined time period is updated as described abovein the second exemplary embodiment instead of calculating the average ofthe time period from the timing at which the detection of the rotationalradius starts to the timing of the start of capture. In this case, thelens CPU 6808 calculates the matching status determination value byusing a latest updated value in a time period immediately before thecapture starts.

The output correction unit 309 calculates a parallel vibrationcorrection target value by multiplying the output (vibration angle) ofthe HPF integration filter 301 of the gyro 6807 p by the rotationalradius L, which is input from the rotational radius averaging unit 5401,and the imaging magnification, which is calculated based on the zoom andfocus information 302.

The driving unit 6809 drives the vibration correction unit 6806 based onthe angular vibration correction target value from the sensitivityadjustment unit 303 during the time period in which the release button6804 a has been half-pressed to correct the angular vibration.

When the release button 6804 a is fully pressed (during the exposuretime period), the driving unit 6809 drives the vibration correction unit6806 based on the angular vibration correction target value and theparallel vibration correction target value from the output correctionunit 309.

With the above-described configuration, the present exemplary embodimentcan calculate a rotational radius L by using the average value of therotational radiuses L calculated for each frequency. Accordingly, thepresent exemplary embodiment can stably execute the correction of theparallel vibration.

In the example illustrated in FIG. 54, a plurality of BPFs is used.However, the present exemplary embodiment is not limited to this. Forexample, it is also useful if Fourier transform is used to calculate therotational radius L at each frequency and calculate a rotational radiusL by using the average of the rotational radiuses L, as described abovewith reference to FIG. 53.

A fifth exemplary embodiment of the present invention is describedbelow. FIG. 56 illustrates an exemplary configuration of the imagestabilization control apparatus included in a single-lens reflex cameraaccording to the present exemplary embodiment.

With respect to the rotational radius L, the present exemplaryembodiment calculates a rotational radius L at a frequency at which thevibration velocity becomes highest instead of calculating the averagevalue of the rotational radiuses L at a plurality of frequency levels.

Accordingly, the configuration of the present exemplary embodimentillustrated in FIG. 56 is different from the above-describedconfiguration of the fourth exemplary embodiment illustrated in FIG. 54in the following points.

-   -   The present exemplary embodiment includes maximum amplitude        detection units 5601 through 5603.    -   The present exemplary embodiment includes a frequency selection        unit 5604 instead of the rotational radius averaging unit 5401.

The present exemplary embodiment uses three pairs of BPFs in calculatingthe rotational radius L as described above with reference to FIG. 48.

An output signal from each of the maximum amplitude detection units 5601through 5603 is input to the frequency selection unit 5604. Thefrequency selection unit 5604 selects a frequency at which the vibrationvelocity becomes highest. In addition, the frequency selection unit 5604outputs the rotational radius L (a signal output from either one of thecomparison units 3905, 3906, and 4806) at the selected frequency to theoutput correction unit 309.

The output signals from the maximum amplitude detection units 5601through 5603 are described in detail below.

The maximum amplitude detection units 5602 and 5603 each calculatemaximum and minimum values of the velocity within the period for each ofthe sampling periods 5102 through 5104 (FIG. 51) and 5202 through 5204(FIG. 52). Furthermore, the maximum amplitude detection units 5602 and5603 each calculate the maximum amplitudes 5105 through 5107 (FIG. 51)and 5205 through 5207 (FIG. 52) based on the difference between themaximum and minimum values of the velocity.

Similarly, the maximum amplitude detection unit 5601 calculates maximumand minimum values of the velocity within the period of the samplingperiods 5002 through 5004 (FIG. 50). Furthermore, the maximum amplitudedetection unit 5601 calculates the maximum amplitudes 5005 through 5007based on the difference between the maximum and minimum values of thevelocity.

When the capture starts, the maximum amplitude detection unit 5601further calculates an average of the maximum amplitudes calculated foreach sampling period. In addition, the maximum amplitude detection unit5601 outputs a signal of the average value to the frequency selectionunit 5604.

With respect to the maximum amplitude signal, it is also useful if themoving average for each predetermined time period is updated asdescribed above in the second exemplary embodiment instead of using theaverage of the time periods from the detection of the rotational radiusto the start of capture.

The frequency selection unit 5604 selects a frequency at which thevibration velocity is highest among the maximum amplitudes for eachfrequency level calculated immediately before the start of capture, andoutputs the output of the comparison unit 3905, 3906, or 4806corresponding the selected frequency to the output correction unit 309.The comparison units 3905, 3906, and 4806 each calculate the rotationalradius L for each sampling period. When the capture starts, thecomparison units 3905, 3906, and 4806 each further calculate an averageof the rotational radiuses L calculated for each sampling period. Withrespect to the signal indicating the rotational radius L, it is alsouseful if the moving average for each predetermined time period isupdated as described above in the second exemplary embodiment instead ofusing the average of the time periods from the detection of therotational radius to the start of capture.

As described above, in the present exemplary embodiment, the detectionof the rotational radius L for each frequency is continued to a timingimmediately before the start of capture and the frequency selection unit5604 selects a rotational radius L at a frequency at which the vibrationvelocity becomes highest.

The output correction unit 309 calculates a parallel vibrationcorrection target value by multiplying the output (vibration angle) ofthe HPF integration filter 301 of the gyro 6807 p by the rotationalradius L, which is input from the frequency selection unit 5604, and theimaging magnification, which is calculated based on the zoom and focusinformation 302.

The driving unit 6809 drives the vibration correction unit 6806 based onthe angular vibration correction target value from the sensitivityadjustment unit 303 during the time period in which the release button6804 a has been half-pressed to correct the angular vibration.

When the release button 6804 a is fully pressed (during the exposuretime period), the driving unit 6809 drives the vibration correction unit6806 based on the angular vibration correction target value and theparallel vibration correction target value from the output correctionunit 309.

With the above-described configuration, the present exemplary embodimentcan calculate a rotational radius L at a frequency at which thevibration velocity becomes highest. Accordingly, the present exemplaryembodiment can prevent degradation of the accuracy of correcting theparallel vibration when a great vibration occurs at a specificfrequency.

In the example illustrated in FIG. 56, a plurality of BPFs is used.However, the present exemplary embodiment is not limited to this. Forexample, it is also useful if Fourier transform is used to calculate therotational radius L at each frequency and calculate a rotational radiusL by using the average of the rotational radiuses L, as described abovewith reference to FIG. 53.

The present exemplary embodiment uses the maximum amplitude of thevelocity output calculated by integrating the output of the ACC 101 p inselecting the frequency. However, the present exemplary embodiment isnot limited to this. For example, it is also useful if the displacementof vibration, which is calculated by second-order integrating the outputof the ACC 101 p, the output of the gyro 6807 p, or an angle outputcalculated by integrating the output of the gyro 6807 p is used.

A sixth exemplary embodiment of the present invention is described indetail below. FIG. 57 illustrates an exemplary configuration of theimage stabilization control apparatus included in a single-lens reflexcamera according to the present exemplary embodiment.

The configuration of the present exemplary embodiment illustrated inFIG. 57 is different from the above-described configuration of the fifthexemplary embodiment illustrated in FIG. 56 in the following point.

-   -   With respect to the rotational radius L, the present exemplary        embodiment selects a frequency that utilizes the rotational        radius L according to the orientation of the camera instead of        the rotational radius L at a frequency at which the vibration        velocity becomes highest.

Accordingly, the configuration illustrated in FIG. 57 is different fromthe configuration illustrated in FIG. 56 in the following point. Thepresent exemplary embodiment includes an orientation detection unit 5701instead of the maximum amplitude detection units 5601 through 5603.

A signal of the output of the ACC 101 p is input to the orientationdetection unit 5701. Furthermore, although not illustrated in FIG. 57, asignal from the ACC 101 y, which executes detection in a directionorthogonal to the detection direction of the ACC 101 p, and a signalfrom the ACC 101 z, which executes detection in a direction orthogonalto the detection directions of the ACC 101 p and the ACC 101 y, areinput to the orientation detection unit 5701. The orientation detectionunit 5701 uses the signals from the ACCs 101 p, 101 y, and 101 z todetect the orientation of the camera.

FIGS. 58A through 58H each illustrate an orientation of the camera to bedetected and the detection direction of the ACC in each cameraorientation.

In the example illustrated in FIGS. 58A through 58H, an arrow 101 paindicates the direction of detection of the acceleration of the ACC 101p. An arrow 101 ya indicates the direction of detection of theacceleration of the ACC 101 y. An arrow 101 za indicates the directionof detection of the acceleration of the ACC 101 z. An arrow 5809indicates the direction of gravity.

An orientation 5801 (FIG. 58A) indicates that the camera is orientedupward. An orientation 5802 (FIG. 58B) indicates that the camera ishorizontally held (in a landscape-capture orientation) and is orientedin a skewed orientation by 45 degrees upward. An orientation 5803 (FIG.58C) indicates that the camera is vertically held (in a portrait-captureorientation) and is oriented in a skewed orientation by 45 degreesupward.

An orientation 5804 (FIG. 58D) indicates that the camera is horizontallyheld in a landscape-capture orientation. An orientation 5805 (FIG. 58E)indicates that the camera is vertically held in a portrait-captureorientation.

An orientation 5806 (FIG. 58F) indicates that the camera is horizontallyheld (in a landscape-capture orientation) and is oriented in a skewedorientation by 45 degrees downward. An orientation 5807 (FIG. 58G)indicates that the camera is vertically held (in a portrait-captureorientation) and is oriented in a skewed orientation by 45 degreesdownward. An orientation 5808 (FIG. 58H) indicates that the camera isoriented downward.

A rotational radius L may change according to the orientation of holdingthe camera. In this regard, the rotational radius L becomes smaller asthe frequency becomes higher in the orientation 5804, for example. Inthe orientations 5801 and 5808, a low-frequency parallel vibrationbecomes dominant.

When the photographer vertically holds the camera in a portrait-captureorientation as in the orientation 5805, a high-frequency great parallelvibration occurs in the direction illustrated with the arrow 101 ya.Accordingly, in the orientation 5804, it is useful if the parallelvibration is corrected by using an average value of the rotationalradiuses L calculated based on the outputs of the ACC and the gyro ateach frequency of 2 Hz, 5 Hz, and 8 Hz.

In the orientations 5801 and 5808, it is useful if the parallelvibration is corrected by using the rotational radius L calculated basedon the outputs of the ACC and the gyro at 2 Hz. In the orientations5805, it is useful if the parallel vibration is corrected by using therotational radius L calculated based on the outputs of the ACC and thegyro at 8 Hz.

The frequency selection unit 5604 calculates an average of the signalsfrom the comparison units 3905, 3906, and 4806 according to the signalfrom the orientation detection unit 5701. Alternatively, the frequencyselection unit 5604 selects the signal from the comparison unit 3905 orthe signal from the comparison unit 4806. The frequency selection unit5604 outputs the rotational radius L included in the signal to theoutput correction unit 309.

The output correction unit 309 calculates a parallel vibrationcorrection target value by multiplying the output (vibration angle) ofthe HPF integration filter 301 of the gyro 6807 p by the rotationalradius L, which is input from the output correction unit 309, and theimaging magnification, which is calculated based on the zoom and focusinformation 302.

The driving unit 6809 drives the vibration correction unit 6806 based onthe angular vibration correction target value from the sensitivityadjustment unit 303 during the time period in which the release button6804 a has been half-pressed to correct the angular vibration.

When the release button 6804 a is fully pressed (during the exposuretime period), the driving unit 6809 drives the vibration correction unit6806 based on the angular vibration correction target value and theparallel vibration correction target value from the output correctionunit 309.

With the above-described configuration, the present exemplary embodimentcan calculate a rotational radius L at a frequency at which thevibration is most dominantly caused to occur according to the captureorientation of the camera. Accordingly, the present exemplary embodimentcan stably and constantly correct the parallel vibration before startingcapture.

A seventh exemplary embodiment of the present invention is describedbelow. FIG. 59 illustrates an exemplary configuration of the imagestabilization control apparatus included in a single-lens reflex cameraaccording to the present exemplary embodiment.

The configuration of the present exemplary embodiment illustrated inFIG. 59 is different from the above-described configuration of the sixthexemplary embodiment illustrated in FIG. 57 in the following point. Thepresent exemplary embodiment uses only one BPF instead of using aplurality of BPFs and varies an extraction frequency of the BPFaccording to the orientation of the camera.

Accordingly, the configuration illustrated in FIG. 59 is different fromthe configuration illustrated in FIG. 57 in the following points.

1) The present exemplary embodiment does not include the gyro BPF 1 unit3901, the ACC BPF 1 unit 3902, the gyro BPF 2 unit 3903, the ACC BPF 2unit 3904, the gyro BPF 3 unit 4804, the ACC BPF 3 unit 4805, and thefrequency selection unit 5604. In addition, in the present exemplaryembodiment, the output of the gyro 6807 p and the output of the ACC 101p (the output of the HPF phase adjustment unit 304 and the output of thegain correction unit 4104) are input to a gyro variable BPF unit 5901and an ACC variable BPF unit 5902, respectively.

2) In the present exemplary embodiment, the output of the orientationdetection unit 5701 is input to the gyro variable BPF unit 5901 and theACC variable BPF unit 5902.

3) A rotational radius calculation in-process signal from the comparisonunit 3905 is input to the gain return inhibition unit 4102.

If the camera is oriented in the orientation 5804, the orientationdetection unit 5701 sets a BPF extraction frequency of the gyro variableBPF unit 5901 and the ACC variable BPF unit 5902 at 5 Hz. If the camerais oriented in the orientation 5805, the orientation detection unit 5701sets a BPF extraction frequency of the gyro variable BPF unit 5901 andthe ACC variable BPF unit 5902 at 8 Hz. If the camera is oriented in theorientation 5801 or 5808, the orientation detection unit 5701 sets a BPFextraction frequency of the gyro variable BPF unit 5901 and the ACCvariable BPF unit 5902 at 2 Hz.

The frequency for extracting the rotational radiuses L can be determinedby previously detecting the orientation of the camera. Accordingly, inthis case, it is not necessary to provide a plurality of BPFs to thecamera. Furthermore, in this case, the operation load can be reduced.Accordingly, the present exemplary embodiment can implement a parallelvibration correction system useful in applying to a consumer product.

The comparison unit 3905 calculates a rotational radius L based on theoutputs of the gyro variable BPF unit 5901 and the ACC variable BPF unit5902. Furthermore, the comparison unit 3905 outputs the calculatedrotational radius L to the output correction unit 309.

The output correction unit 309 calculates a parallel vibrationcorrection target value by multiplying the output (vibration angle) ofthe HPF integration filter 301 of the gyro 6807 p by the rotationalradius L, which is input from the comparison unit 3905, and the imagingmagnification, which is calculated based on the zoom and focusinformation 302.

The driving unit 6809 drives the vibration correction unit 6806 based onthe angular vibration correction target value from the sensitivityadjustment unit 303 during the time period in which the release button6804 a has been half-pressed to correct the angular vibration.

When the release button 6804 a is fully pressed (during the exposuretime period), the driving unit 6809 drives the vibration correction unit6806 based on the angular vibration correction target value and theparallel vibration correction target value from the output correctionunit 309.

As described above, the present exemplary embodiment sets a BPFs forextracting a frequency that is most dominant in causing the vibrationaccording to the orientation of the camera during capture. Accordingly,it is not necessary to provide a plurality of BPFs to the camera.Furthermore, the operation load can be reduced. Accordingly, the presentexemplary embodiment can implement a parallel vibration correctionsystem useful in applying to a consumer product.

An eighth exemplary embodiment of the present invention is describedbelow. FIG. 60 illustrates an exemplary configuration of the imagestabilization control apparatus included in a single-lens reflex cameraaccording to the present exemplary embodiment.

The configuration of the present exemplary embodiment illustrated inFIG. 60 is different from the above-described configuration of theseventh exemplary embodiment illustrated in FIG. 59 in the followingpoint. The present exemplary embodiment, uses a variable frequency forone BPF as in the seventh exemplary embodiment.

However, in the present exemplary embodiment, the extraction frequencychanges with the lapse of time. That is, the present exemplaryembodiment changes the break frequency of the BPF at intervals of apredetermined period (e.g., a period twice longer than the period 2801(FIG. 28)).

More specifically, the present exemplary embodiment takes one second atthe break frequency of 2 Hz. Then, the present exemplary embodimentcalculates the rotational radius L based on the maximum amplitudes ofthe velocity signal and the angular velocity signal during theone-second time period.

Furthermore, the present exemplary embodiment takes 0.4 seconds at thebreak frequency of 5 Hz. Then, the present exemplary embodimentcalculates the rotational radius L based on the maximum amplitudes ofthe velocity signal and the angular velocity signal during the0.4-second time period. In addition, the present exemplary embodimenttakes 0.25 seconds at the break frequency of 8 Hz. Then, the presentexemplary embodiment calculates the rotational radius L based on themaximum amplitudes of the velocity signal and the angular velocitysignal during the 0.25-second time period.

To paraphrase this, the rotational radius (correction value) L iscalculated based on a first signal and a second signal in a plurality ofdifferent frequency bands chronologically extracted as a first frequencyband. Accordingly, the configuration illustrated in FIG. 60 is differentfrom the configuration illustrated in FIG. 59 in the following point.

The present exemplary embodiment includes a BPF control unit 6001instead of the orientation detection unit 5701. An output signal fromthe BPF control unit 6001 is input to the gyro variable BPF unit 5901and the ACC variable BPF unit 5902. The BPF control unit 6001 sets theBPF break frequency at 2 Hz, 5 Hz, and 8 Hz for the gyro variable BPFunit 5901 and the ACC variable BPF unit 5902 from the start of detectionof rotational radius (i.e., from the time t2 (FIG. 30)) and uses the BPFbreak frequency in a circulating manner.

The BPF break frequency can be circulatingly used in such a descendingor ascending numeric order as “2 Hz→5 Hz→8 Hz→5 Hz→2 Hz→5 Hz” in orderto prevent a rapid frequency change (e.g., 8 Hz→2 Hz) during thecirculation. This is because if the frequency is rapidly changed, ittakes time to stabilize the BPF after the break frequency is changed.

The comparison unit 3905 calculates the rotational radiuses L at the BPFbreak frequency of each of the gyro variable BPF unit 5901 and the ACCvariable BPF unit 5902. When capture starts, the comparison unit 3905calculates an average of the rotational radiuses L and outputs theaverage to the output correction unit 309. Alternatively, the comparisonunit 3905 can update a moving average of the rotational radiuses L(e.g., an average of three rotational radiuses L) at each breakfrequency. In this case, when capture starts, the comparison unit 3905outputs a latest rotational radius L to the output correction unit 309.

The output correction unit 309 calculates a parallel vibrationcorrection target value by multiplying the output (vibration angle) ofthe HPF integration filter 301 of the gyro 6807 p by the rotationalradius L, which is input from the comparison unit 3905, and the imagingmagnification, which is calculated based on the zoom and focusinformation 302.

The driving unit 6809 drives the vibration correction unit 6806 based onthe angular vibration correction target value from the sensitivityadjustment unit 303 during the time period in which the release button6804 a has been half-pressed to correct the angular vibration.

When the release button 6804 a is fully pressed (during the exposuretime period), the driving unit 6809 drives the vibration correction unit6806 based on the angular vibration correction target value and theparallel vibration correction target value from the output correctionunit 309.

In the present exemplary embodiment, a chronologically variable BPFextraction frequency is used. Accordingly, it is not necessary toprovide a plurality of BPFs to the camera. Furthermore, the presentexemplary embodiment can reduce the operation load. Accordingly, thepresent exemplary embodiment can implement a parallel vibrationcorrection system useful in applying to a consumer product.

A ninth exemplary embodiment of the present invention is describedbelow. In the above-described exemplary embodiments 1 through 8, animage stabilization control apparatus is applied to a single-lens reflexcamera having an exchangeable lens. However, the present invention isnot limited to this. For example, the present invention can be appliedto a compact camera and a video camera in which the lens is integrallymounted on the apparatus body or to a camera system assembled in aportable device.

In the above-described first through eighth exemplary embodiments, theACCs 101 p and 101 y are used for detecting parallel vibration. Thepresent exemplary embodiment uses a sensor other than an ACC to detectparallel vibration.

FIG. 61 illustrates an exemplary configuration of a camera and an imagestabilization control apparatus included in the camera according to thepresent exemplary embodiment. A digital compact camera is illustrated inFIG. 61. However, a single-lens reflex camera can be used.

As a characteristic feature of the present exemplary embodiment, thepresent exemplary embodiment uses the vibration correction unit 6806 todetect parallel vibration occurring around the principal point of theimaging optical system.

A method for detecting an angular velocity by using a vibrationcorrection unit can be executed by observing and detecting the amount ofcurrent flowing through a driving coil of the vibration correction unit.Driven components of the vibration correction unit includes a correctionlens, a supporting frame of the correction lens, and a driving coil (ora driving magnet). Accordingly, the mass of the vibration correctionunit is sufficiently larger than the angular velocity detection mass ofthe ACC. The accuracy of detecting the angular velocity increases if theangular velocity detection mass becomes greater. Accordingly, in thiscase, the angular velocity can be detected with high accuracy by usingthe vibration correction unit.

However, in this regard, the driven components of the vibrationcorrection unit are generally in contact with the fixed componentsthereof by sliding contact. The frictional force from the slidingcontact may degrade the angular velocity detection accuracy.

In this regard, in calculating a rotational radius L by comparison withthe angular velocity signal, the present invention executes thecomparison by extracting a specific frequency component only.Accordingly, the present invention can suppress or reduce the influencefrom the slide friction.

The slide friction can be prevented if a vibration correction unitillustrated in FIGS. 62A and 62B is used. FIGS. 62A and 62B are a planview and a cross section, respectively, of an example of a vibrationcorrection unit 6201 (equivalent to the vibration correction unit 6806in FIG. 61), which is elastically supported with wires.

Referring to FIGS. 62A and 62B, a correction lens 6202 is supported by asupporting frame 6203. The supporting frame 6203 includes driving coils6207 a and 6207 b and a supporting and wiring board 6209 for connectingthe driving coils 6207 a and 6207 b to wires.

Wires 6205 a through 6205 d are provided between a base substrate 6204and the supporting and wiring board 6209, which are fixed units.

The wires 6205 a through 6205 d are soldered on the base substrate 6204and the supporting and wiring board 6209 at solder portions 6211 athrough 6211 d and 6212 a through 6212 d, although the solder portions6211 b, 6211 d, 6212 b, and 6212 d are not illustrated in FIGS. 62A and62B.

In soldering the wires 6205 a through 6205 d on the base substrate 6204and the supporting and wiring board 6209, a dedicated tool is used toregulate the clearance and a tilt between the correction lens 6202 andthe base substrate 6204. Accordingly, the accuracy of mounting thecorrection lens 6202 onto the base substrate 6204 can be increased.

Power is supplied to the driving coils 6207 a and 6207 b from the basesubstrate 6204 via the wires 6205 a through 6205 d and patterns 6206 athrough 6206 d on the base substrate 6209. On the base substrate 6204,which faces the driving coils 6207 a and 6207 b, includes permanentmagnets 6208 a and 6208 b, which are mounted thereon. The permanentmagnets 6208 a and 6208 b are illustrated with broken-line rectangles inFIG. 62A.

Accordingly, if current is fed through the driving coils 6207 a and 6207b, the correction lens 6202 is driven relative to the optical axis 6210in directions 6213 p and 6213 y due to the balance of current passingthrough the driving coils 6207 a and 6207 b while warping the wires 6205a through 6205 d.

Magnetic, optical, or eddy current (EC) type position detection sensors6215 a and 6215 b are assembled on the base substrate 6204. The positiondetection sensors 6215 a and 6215 b detect the distance between targets6214 a and 6214 b, which are mounted on the base substrate 6209. Outputsfrom the position detection sensors 6215 a and 6215 b are amplified bydifferential amplifiers 6216 a and 6216 b, respectively, to a sufficientlevel. Current is fed through the driving coils 6207 a and 6207 b basedon the amplified signal.

If the outputs of the position detection sensors 6215 a and 6215 b arenegatively fed back into the driving coils 6207 a and 6207 b, thepublicly known positional feedback is implemented. The correction lens6202 is electrically fixed at a point at which the output of each of theposition detection sensors 6215 a and 6215 b is “0”.

The present exemplary embodiment adjusts the bias voltage and the gainof the position detection sensors 6215 a and 6215 b so that the outputof the position detection sensors 6215 a and 6215 b becomes “0” when thecorrection lens 6202 is set on an optical axis of another imagingoptical system (not illustrated). In this case, the correction lens 6202is stably supported at this position.

In this state, if vibration correction target values 6217 a and 6217 b,such as angular vibration or parallel vibration, are input, then thecorrection lens 6202 is driven with high accuracy in a tracking manneraccording to the target value.

Even when no vibration correction target value is input, drivencomponents of the vibration correction unit 6201 are subjected togravity and the acceleration of the parallel vibration. Accordingly, theposition of the correction lens 6202 is changed against the elasticforce of the wires 6205 a through 6205 d.

The position detection sensors 6215 a and 6215 b detect the positionalchange of the correction lens 6202. Furthermore, the wires 6205 athrough 6205 d feeds the driving coils 6207 a and 6207 b with currentthat sets off the positional change. Accordingly, the correction lens6202 can constantly stay at its initial position.

Accordingly, by observing and detecting the current passing through thedriving coils 6207 a and 6207 b, the input gravity and the parallelvibration acceleration can be detected. The present exemplary embodimentutilizes the detected acceleration output to calculate the rotationalradius L in relation to the output from the gyro in the above-describedmanner and to further correct the parallel vibration. If theabove-described supporting method that utilizes the wire is used, theacceleration can be detected with high accuracy because of the absenceof slide friction.

During a time period in which the vibration correction unit is executingthe correction of vibration such as angular vibration, the change in thecurrent may cause a great degradation of the accuracy of detecting theacceleration. In this regard, the present exemplary embodiment executescontrol for electrically feeding back the vibration correction unit 6201to its initial position (the position at which the capture optical axisand the optical axis of the correction lens match) until immediatelybefore the start of capture.

Furthermore, the present exemplary embodiment drives the correction lensonly when the exposure is being executed based on the angular vibrationcorrection target value and the parallel vibration correction targetvalue. Thus, the present exemplary embodiment corrects the image shake.More specifically, the present exemplary embodiment uses the vibrationcorrection unit 6201 as the ACC before the exposure starts and uses thevibration correction unit 6201 as the vibration correction unit afterthe exposure is started.

Accordingly, angular vibration cannot be optically corrected in themanner described above in the first to eighth exemplary embodimentsduring preparation for capture (in which the release button 6804 a isbeing half-pressed).

In this regard, a digital camera can utilize an electronic imagestabilization function. The electronic image stabilization function is afunction for reducing the vibration between taken frames output by theimage sensor by changing the capturing position of the frames accordingto vibration.

If the electronic image stabilization function is used, the capturingposition can be controlled according to the change in motion vectorsbetween frames output by the image sensor or based on the output of thegyros 6807 p and 6807 y. More specifically, in this case, it is alsouseful if the present exemplary embodiment uses the electronic imagestabilization function before the start of capture while when thecapture starts, the present exemplary embodiment drives the correctionlens to execute optical image stabilization.

FIG. 63 is a flow chart illustrating an exemplary flow of theabove-described processing according to the present exemplaryembodiment. In the example illustrated in FIG. 63, steps similar tothose in FIG. 32 are provided with the same step reference number.Accordingly, the description thereof will not be repeated here. Theprocessing according to the flow illustrated in FIG. 63 starts when thecamera is powered on. In synchronization with the powering on of thecamera, the vibration correction unit is electrically held at theinitial position.

Referring to FIG. 63, in step S6301, the lens CPU 6808 detects theacceleration applied on the vibration correction unit 6201 by detectingthe current fed through the driving coil of the vibration correctionunit 6201. At this time, the correction lens of the vibration correctionunit 6201 is positioned almost at the principal point of the entireimaging optical system. Accordingly, the parallel vibration accelerationat the principal point of the imaging optical system is detected in stepS6301. As in step S3202 (FIG. 32), the lens CPU 6808 activates the gyroand drives the AF sensor in step S6301.

In step S6302, the lens CPU 6808 starts electronic image stabilizationagainst the angular vibration. More specifically, the lens CPU 6808changes the capturing position of image signals output from the imagesensor, which are chronologically output based on the output of the gyro(the angular vibration correction target value (the output of thesensitivity adjustment unit 303)) to thereby reduce compositiondeviation occurring due to inter-picture vibration. Then, the lens CPU6808 outputs the image signals on a back LCD monitor (not illustrated).It is also useful if the motion vector between image signals that arechronologically output is calculated and the capturing position of theimage signals is changed based on the calculated value of the motionvector instead of using the signal from the gyro.

In step S6303, the lens CPU 6808 suspends the electronic imagestabilization because the panning of the camera has been detected instep S3207. The processing for suspending the detection of therotational radius is similar to that executed in step S3208 (FIG. 32).In step S6304, the lens CPU 6808 resumes the electronic imagestabilization because the panning of the camera has ended in step S3209.The processing for resuming the detection of the rotational radius issimilar to that executed in step S3210 (FIG. 32).

In step S6305, the lens CPU 6808 suspends the electronic imagestabilization and drives the vibration correction unit 6201 based on theparallel vibration and the angular vibration correction target value.Thus, the lens CPU 6808 starts optical image stabilization. In stepS6306, the lens CPU 6808 suspends the optical image stabilizationbecause the output from the image sensor has been completely accumulated(the exposure has ended) in step S3219. Then, the lens CPU 6808 startsthe electronic image stabilization to correct the angular vibration.

Although the optical image stabilization has been suspended, thedetection of the acceleration is continued by the vibration correctionunit, which has been returned to its initial position and electricallyheld there. When the main power switch is pressed in this state, theholding of the vibration correction unit at its initial position can becancelled.

In step S6307, because a predetermined time period has elapsed since thehalf-press of the release button 6804 a, the lens CPU 6808 suspends theelectronic image stabilization and the correction of the angularvibration. In step S6308, the lens CPU 6808 suspends the detection ofacceleration with the vibration correction unit.

The principal point of the photographic lens and the position of thevibration correction unit change according to the zoom position and thefocusing position. The present exemplary embodiment corrects the changeof the principal point of the photographic lens and the position of thevibration correction unit in the manner described above with referenceto FIG. 38.

As described above, the present exemplary embodiment utilizes thevibration correction unit as the gyro. More specifically, the secondvibration detection unit is used as a unit for detecting the vibrationbased on the current passing through the driving unit of the vibrationcorrection unit, which current is generated due to the vibration, duringthe time period in which the vibration correction and driving unit doesnot operate.

Furthermore, the present exemplary embodiment uses the vibrationcorrection unit as the second vibration detection unit before thecapture starts. Accordingly, it becomes unnecessary to provide adedicated gyro. Accordingly, a small and light-weight camera can beimplemented.

The present exemplary embodiment uses the vibration correction drivingunit to drive the vibration correction unit when the capture operationis being performed. The present exemplary embodiment corrects imageshake in this manner.

Furthermore, the parallel vibration can be detected with high accuracyby using the vibration correction unit described above with reference toFIGS. 62A and 62B. In addition, in the present exemplary embodiment, theelectronic image stabilization is executed during the time period inwhich the vibration correction unit is being used as the ACC.Accordingly, the present exemplary embodiment can execute the correctionof the angular vibration and the detection of the acceleration inparallel to each other.

In addition, the lens CPU 6808 corrects the image shake with the drivingunit, which is a vibration correction driving unit in controllingclipping of images from the imaging unit (image sensor) until thecapture operation starts. When the capture operation is being performed,the lens CPU 6808 drives the vibration correction unit with thevibration correction driving unit to correct the image shake with thevibration correction unit.

A tenth exemplary embodiment of the present invention is describedbelow. FIG. 64 illustrates an exemplary configuration of a camera and animage stabilization control apparatus included in the camera accordingto the present exemplary embodiment. A digital compact camera isillustrated in FIG. 64. It is also useful if a single-lens reflex camerais used.

In the present exemplary embodiment also, parallel vibration is detectedby using a sensor different from the ACC.

As characteristic of the present exemplary embodiment, the presentexemplary embodiment includes a second vibration detection unit, whichis used as a unit for detecting vibration based on the output of theimaging unit (hereinafter may also be referred to as an “image sensor6401”). More specifically, the present exemplary embodiment detects theparallel vibration occurring around the principal point of the imagingoptical system by using an image output of the image sensor 6401.

The method for detecting the vibration and the composition deviation bycomparing the images chronologically output from the image sensor 6401is known as “electronic image stabilization” or “image combination”.However, the electronic image stabilization and the image combinationcannot be applied to still images unless the output from the imagesensor can be nondestructively read.

However, if the above-described method for correcting the angularvelocity output by using a previously calculated rotational radius L asa correction value is used, the output of the image sensor can be used.

More specifically, if a method is used that calculates the rotationalradius L by detecting the vibration based on the image output andcomparing the detection result with the angle based on the angularvelocity output, the angular velocity output can be corrected even whena still image is shot by utilizing a capture preparing state (movingpicture taking state) before capture a still image.

With the above-described configuration, the present exemplary embodimentcan correct the angular velocity output before starting capture of astill image. Accordingly, the image output, which has beenconventionally utilized only in the case of capture moving images, canbe used in the case of capture a still image.

FIG. 65 illustrates exemplary motion vectors according to the presentexemplary embodiment. Referring to FIG. 65, an image 6501 a includes animage of a flower at a specific time. An image 6501 b, which isillustrated with thin lines in FIG. 65, includes an image of the flowerafter a predetermined time period has elapsed (e.g., after 1/30 secondshas elapsed).

The two images have different compositions due to the angular vibrationand the parallel vibration.

The present exemplary embodiment sets a characteristic point at aportion having a high contrast, such as an edge 6503 a of a flower 6502a, which is a main object of the image 6501 a. The present exemplaryembodiment calculates a characteristic point 6503 b, which correspondsto the characteristic point 6503 a, based on positional informationabout the characteristic point 6503 a and information about an edgeimage of a flower 6502 b of the image 6501 b.

Arrows 6504 y and 6504 p indicate horizontal and vertical components ofa motion vector 6504, which connects the two characteristic points.Displacement of vibration on the image can be acquired by combining themotion vector, which has been separated into components in twodirections, for each image.

In this regard, the vertical motion vector 6504 p is described. If themotion vectors between images at specific timings are accumulated, thena waveform 6602 (FIG. 66), which is to be input to a motion vector BPFunit 6403 (FIG. 64), can be acquired.

The motion vector BPF unit 6403 passes only a first frequency bandcomponent (2 Hz, for example) of the waveform 6602. Accordingly, thepresent exemplary embodiment can suppress the noise superposed on themotion vector and the low-frequency deviation that may occur due tomovement of the object. Thus, the present exemplary embodiment candetect only the vibration component with high accuracy.

With respect to the output from the gyro, the present exemplaryembodiment uses an HPF integration delay adjustment unit 6402 to convertthe angular velocity into an angle. Thus, the same dimension as that ofthe motion vector can be set (delay adjustment). The delay adjustment,by which the displacement of the deviation detected based on the outputof the imaging unit and the vibration angle detected by the ACC arecompared to be adjusted, will be described in detail below.

Then, the gyro BPF unit 306 passes only the first frequency bandcomponent of the angle waveform. Accordingly, a low-frequency driftcomponent that may be superposed on the angle waveform can be removed.

In the example illustrated in FIG. 66, a sine wave vibration is appliedto the camera. In the example illustrated in FIG. 66, the time is shownon the horizontal axis. A locus of image deviation X, which is acquiredby accumulating vertical motion vectors between images, is shown on thevertical axis.

The phase of the waveform 6602 is offset from that of a waveform 6601,which is a waveform of the deviation of image occurring due to actualvibration. The deviation of the phase is caused by the delay due to thetime for reading the images with the image sensor 6401.

In this regard, in the present exemplary embodiment, the output from thegyro 6807 p is input to the HPF integration delay adjustment unit 6402.Then, the angular velocity is integrated to be converted into an angle.Then, the delay equivalent to the delay in the image sensor 6401 isadded. Thus, the phase of an output waveform 6603 of the gyro BPF unit306 can be made the same as the phase of the waveform 6602.

In the present exemplary embodiment, if the output signal from the imagesensor 6401 is delayed, the output signal and the angular velocitysignal can be compared with each other by also delaying the angularvelocity signal. This is because a rotational radius L is necessary onlyduring capture and it is not necessary to calculate a rotational radiusL in real time.

In the present exemplary embodiment, the extraction frequency of themotion vector BPF unit 6403 and the gyro BPF unit 306 is set at 2 Hz.This is because only a small amount of high-frequency vibration occurson a digital compact camera.

The comparison unit 3905 calculates a rotational radius L by comparingthe waveforms 6602 and 6603 (X/θ) and outputs a result of thecalculation to the output correction unit 309. The output of the gyro6807 p is converted into a vibration angle by the HPF integration filter301. Then, the output correction unit 309 multiplies the vibration angleby the rotational radius L. Thus, a vibration correction target value isacquired.

In the present exemplary embodiment, the sensitivity adjustment unit 303and the zoom and focus information 302, which are illustrated in FIG.61, are not included in the configuration illustrated in FIG. 64 due tothe following reasons.

The deviation of image detected by the image sensor 6401 alreadyincludes the deviation of image occurring due to the sensitivity, theimaging magnification, which are determined based on the state of zoomand focus, and the angular vibration. Accordingly, if the rotationalradius L is calculated based on the output of the image sensor 6401 inthis case, the image deviation due to the sensitivity, the imagingmagnification, and the angular vibration in the calculated rotationalradius L has already been corrected.

As described above, the present exemplary embodiment calculates therotational radius L based on the image captured by the image sensor6401. Accordingly, it becomes unnecessary to correct the sensitivity andthe imaging magnification. Furthermore, in this case, it becomesunnecessary to individually correct the angular vibration and theparallel vibration. Thus, the present exemplary embodiment can correctthe parallel vibration regardless of the principal point of thephotographic lens.

Before the capture starts, the present exemplary embodiment executes theelectronic image stabilization until the capture starts, but does notdrive the vibration correction unit, as in the ninth exemplaryembodiment, in order to increase the accuracy of detecting the motionvector between the images output by the image sensor 6401 by causing thevibration correction unit to stay at its initial position.

If a motion vector of the image sensor is calculated in a state in whichthe vibration correction unit is driven and the angular vibration iscorrected, the motion vector between the images output by the imagesensor is the image deviation occurring due to the parallel vibrationcomponent.

In this case, it is useful if the angular vibration correction targetvalue is calculated by using the sensitivity adjustment unit 303 and thezoom and focus information 302, the parallel vibration correction targetvalue is added to the calculated angular vibration correction targetvalue, and the vibration is corrected during capture, as illustrated inFIG. 67. Even in this case, it is not necessary to correct the principalpoint of the photographic lens and the imaging magnification incalculating the parallel vibration correction target value.

According to the above-described exemplary embodiments the presentinvention, the output of the angular velocity detection unit iscorrected with the output of the acceleration detection unit in aspecific frequency band, or alternatively, the output of the angularvelocity detection unit is corrected with a motion vector signal fromthe imaging unit in a specific frequency band.

With the above-described configuration, the present exemplary embodimentcan implement a small-sized image stabilization system with a highmobility and stability even in macro capture. More specifically, thepresent exemplary embodiment having the above-described configurationcan correct image shake occurring due to parallel vibration with highaccuracy.

In the first through tenth exemplary embodiments of the presentinvention, parallel vibration is corrected by an exemplary imagestabilization control apparatus included in a digital single-lens reflexcamera or a digital compact camera. However, because the imagestabilization control apparatus according to an exemplary embodiment ofthe present invention can be implemented in a small-sized system havinga high performance, the present invention is not limited to this. Forexample, the present invention can be implemented in capture a stillimage with a video camera or in capture a still image with a monitoringcamera, a web camera, or a mobile phone.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications, equivalent structures, and functions.

This application claims the benefit of Japanese Patent Application No.2008-183426, filed Jul. 15, 2008, which is hereby incorporated byreference herein in its entirety.

1. An image stabilization control apparatus having an instruction unitto allow a user to instruct the image stabilization control apparatus toexecute image capture preparation operations and image captureoperations, comprising: a vibration correction unit configured tocorrect image shake occurring due to vibration applied to the imagestabilization control apparatus; a first vibration detection unitconfigured to detect and output an angular velocity of the vibration; asecond vibration detection unit configured to detect and output anacceleration of the vibration; a calculation unit configured tocalculate a correction value based on the outputs of the first andsecond vibration detection units; an output correction unit configuredto correct the output of the first vibration detection unit using thecorrection value and to output the corrected output; and a driving unitconfigured to drive the vibration correction unit based on either theoutput of the first vibration detection unit or the output of the outputcorrection unit, wherein, during the image capture operations, theoutput correction unit being configured to correct the output of thefirst vibration detection unit using the correction value calculatedbefore an execution of the image capture operations is instructed by theinstruction unit.
 2. The image stabilization control apparatus accordingto claim 1, wherein the calculation unit starts to calculate of thecorrection value when an execution of the image capture preparationoperations is instructed by the instruction unit.
 3. The imagestabilization control apparatus according to claim 1, wherein thecalculation unit stops calculating of the correction value when anexecution of the image capture operations is instructed by theinstruction unit.
 4. The image stabilization control apparatus accordingto claim 3, wherein the calculation unit is configured to calculate anaverage value of the correction values calculated until the execution ofthe image capture operations is instructed by the instruction unit andis configured to output the average value to the output correction unit.5. The image stabilization control apparatus according to claim 1,wherein the driving unit is configured to drive the vibration correctionunit based on the output of the first vibration detection unit duringthe image capture preparation operations.
 6. The image stabilizationcontrol apparatus according to claim 5, wherein the calculation unit isconfigured to calculate the average value of the correction valuescalculated in each predetermined period and is configured to output thelatest average value of the correction value, when the execution of theimage capture operations is instructed by the instruction unit, to theoutput correction unit.
 7. The image stabilization control apparatusaccording to claim 5, wherein the calculation unit is configured tocalculate and update the average value of the correction values by amoving average method.
 8. The image stabilization control apparatusaccording to claim 1, further comprising an imaging optical system,wherein the first vibration detection unit is an angular velocity meter,wherein the second vibration detection unit is an accelerometer, andwherein the correction value is equivalent to a distance from a positionproximity to a principal point of the imaging optical system to arotational center of the vibration, the distance is calculated accordingto a signal based on an output of the angular velocity meter and asignal based on an output of the accelerometer.
 9. The imagestabilization control apparatus according to claim 1, further comprisingan imaging optical system, wherein the first vibration detection unit isan angular velocity meter, wherein the driving unit includes a drivingcoil and is configured to drive the vibration correction unit by feedinga current to the driving coil, and wherein the second vibrationdetection unit is configured to detect vibration based on the currentflowing through the driving coil due to the vibration in a state inwhich the driving unit is not driven.
 10. The image stabilizationcontrol apparatus according to claim 8, wherein the vibration correctionunit is used as the second vibration detection unit until the executionof the image capture operations is instructed by the instruction unit.11. The image stabilization control apparatus according to claim 10,wherein the output correction unit is further configured to correct theoutput of the first vibration detection unit using a pre-storedcorrection value if a length of a time period for calculating thecorrection value is shorter than a length of a predetermined timeperiod.
 12. The image stabilization control apparatus according to claim1, wherein the output correction unit is further configured to correctthe output of the first vibration detection unit using a pre-storedcorrection value if the correction value is greater than a predeterminedvalue.
 13. The image stabilization control apparatus according to claim1, wherein the output correction unit is further configured to correctthe output of the first vibration detection unit using a pre-storedcorrection value if the output of the first vibration detection unit issmaller than a predetermined value.
 14. The image stabilization controlapparatus according to claim 1, wherein the output correction unit isfurther configured to correct the output of the first vibrationdetection unit during a mechanism of the image stabilization controlapparatus is moving.
 15. The image stabilization control apparatusaccording to claim 1, further comprising a reliability determinationunit configured to determine reliability of the correction value, andwherein the reliability determination unit is configured to determinethat the reliability of the correction value is low if a length of atime period for calculating the correction value is shorter than alength of a predetermined time period.
 16. The image stabilizationcontrol apparatus according to claim 1, further comprising a reliabilitydetermination unit configured to determine reliability of the correctionvalue, and wherein the reliability determination unit is configured todetermine that the reliability of the correction value is low if thecorrection value is greater than a predetermined value.
 17. The imagestabilization control apparatus according to claim 1, further comprisinga reliability determination unit configured to determine reliability ofthe correction value, and wherein the reliability determination unit isconfigured to determine that the reliability is low if the output of thefirst vibration detection unit is smaller than a predetermined value.18. The image stabilization control apparatus according to claim 1,further comprising a reliability determination unit configured todetermine reliability of the correction value, and wherein thereliability determination unit is configured to determine that thereliability is low during the mechanism is moving.
 19. The imagestabilization control apparatus according to claim 1, further comprisinga reliability determination unit configured to determine reliability ofthe correction value, and wherein if it is determined by the reliabilitydetermination unit that the reliability is low, the output correctionunit is configured to use a previously stored correction value tocorrect the output of the first vibration detection unit.
 20. An imagingapparatus comprising the image stabilization control apparatus accordingto claim
 1. 21. An image stabilization control apparatus including animaging optical system whose imaging magnification is variable and aninstruction unit to allow a user to instruct the image stabilizationcontrol apparatus to execute image capture preparation operations andimage capture operations, the image stabilization control apparatuscomprising: a vibration correction unit configured to correct imageshake occurring due to vibration applied to the image stabilizationcontrol apparatus; a first vibration detection unit configured to detectand output an angular velocity of the vibration; a second vibrationdetection unit configured to detect and output an acceleration of thevibration; a calculation unit configured to calculate a correction valuebased on the outputs of the first and second vibration detection units;an output correction unit configured to correct the output of the firstvibration detection unit using the correction value and to output thecorrected output; and a driving unit configured to drive the vibrationcorrection unit based on either the output of the first vibrationdetection unit or the output of the output correction unit, a principalpoint movement detection unit configured to detect and output a changeof a principal point of the imaging optical system due to a change ofthe imaging magnification; and a correction value correction unitconfigured to correct the correction value based on an output of theprincipal point moving detection unit.
 22. The image stabilizationcontrol apparatus according to claim 21, wherein the correction valuecorrection unit is configured to correct the correction value such thatan accuracy of correcting image shake based on the output of the outputcorrection unit becomes maximum when the imaging magnification of theimaging optical system is maximum.
 23. The image stabilization controlapparatus according to claim 21, wherein the second vibration detectionunit is located at the principal point of the imaging optical systemwhen the imaging magnification of the imaging optical system is maximum.24. The image stabilization control apparatus according to claim 21,wherein the first vibration detection unit is an angular velocity meter,wherein the second vibration detection unit is an accelerometer, andwherein the correction value is equivalent to a distance from a positionproximity to the principal point of the imaging optical system, which iscalculated according to a signal based on an output of the angularvelocity meter and a signal based on an output of the accelerometer, toa rotational center of the vibration.
 25. The image stabilizationcontrol apparatus according to claim 21, further comprising an imagingoptical system, wherein the first vibration detection unit is an angularvelocity meter, wherein the driving unit includes a driving coil and isconfigured to drive the vibration correction unit by feeding a currentto the driving coil, and wherein the second vibration detection unit isconfigured to detect vibration based on the current flowing through thedriving coil due to the vibration in a state in which the driving unitis not driven.
 26. The image stabilization control apparatus accordingto claim 25, wherein the vibration correction unit is used as the secondvibration detection unit until the execution of the image captureoperations is instructed by the instruction unit.
 27. The imagestabilization control apparatus according to claim 21, wherein theoutput correction unit is further configured to correct the output ofthe first vibration detection unit using a pre-stored correction valueif a length of a time period for calculating the correction value isshorter than a length of a predetermined time period.
 28. The imagestabilization control apparatus according to claim 21, wherein theoutput correction unit is further configured to correct the output ofthe first vibration detection unit using a pre-stored correction valueif the correction value is greater than a predetermined value.
 29. Theimage stabilization control apparatus according to claim 21, wherein theoutput correction unit is further configured to correct the output ofthe first vibration detection unit using a pre-stored correction valueif the output of the first vibration detection unit is smaller than apredetermined value.
 30. The image stabilization control apparatusaccording to claim 21, wherein the output correction unit is furtherconfigured to correct the output of the first vibration detection unitduring a mechanism of the image stabilization control apparatus ismoving.
 31. The image stabilization control apparatus according to claim21, further comprising a reliability determination unit configured todetermine reliability of the correction value, and wherein thereliability determination unit is configured to determine that thereliability of the correction value is low if a length of a time periodfor calculating the correction value is shorter than a length of apredetermined time period.
 32. The image stabilization control apparatusaccording to claim 21, further comprising a reliability determinationunit configured to determine reliability of the correction value, andwherein the reliability determination unit is configured to determinethat the reliability of the correction value is low if the correctionvalue is greater than a predetermined value.
 33. The image stabilizationcontrol apparatus according to claim 21, further comprising areliability determination unit configured to determine reliability ofthe correction value, and wherein the reliability determination unit isconfigured to determine that the reliability is low if the output of thefirst vibration detection unit is smaller than a predetermined value.34. The image stabilization control apparatus according to claim 21,further comprising a reliability determination unit configured todetermine reliability of the correction value, and wherein thereliability determination unit is configured to determine that thereliability is low during the mechanism is moving.
 35. The imagestabilization control apparatus according to claim 21, furthercomprising a reliability determination unit configured to determinereliability of the correction value, and wherein if it is determined bythe reliability determination unit that the reliability is low, theoutput correction unit is configured to use a previously storedcorrection value to correct the output of the first vibration detectionunit.
 36. An imaging apparatus comprising the image stabilizationcontrol apparatus according to claim
 21. 37. An image stabilizationcontrol apparatus having an instruction unit to allow a user to instructthe image stabilization control apparatus to execute image capturepreparation operations and image capture operations, the imagestabilization control apparatus comprising: a vibration correction unitconfigured to correct image shake occurring due to vibration applied tothe image stabilization control apparatus; a first vibration detectionunit configured to detect and output an angular velocity of thevibration; a second vibration detection unit configured to detect andoutput an acceleration of the vibration; a calculation unit configuredto calculate a correction value based on the outputs of the first andsecond vibration detection units; an output correction unit configuredto correct the output of the first vibration detection unit using thecorrection value and to output the corrected output; and a driving unitconfigured to drive the vibration correction unit based on either theoutput of the first vibration detection unit or the output of the outputcorrection unit, a reliability determination unit configured todetermine reliability of the correction value, wherein if it isdetermined by the reliability determination unit that the reliability islow, the output correction unit is configured to use a previously storedcorrection value to correct the output of the first vibration detectionunit.
 38. The image stabilization control apparatus according to claim37, wherein the reliability determination unit is configured todetermine that the reliability of the correction value is low if thecorrection value is greater than a predetermined value.
 39. The imagestabilization control apparatus according to claim 37, wherein thereliability determination unit is configured to determine that thereliability is low if the output of the first vibration detection unitis smaller than a predetermined value.
 40. The image stabilizationcontrol apparatus according to claim 37, wherein the reliabilitydetermination unit is configured to determine that the reliability islow during the mechanism is moving.
 41. An imaging apparatus comprisingthe image stabilization control apparatus according to claim
 37. 42. Animaging apparatus having an instruction unit to allow a user to instructthe image stabilization control apparatus to execute image capturepreparation operations and image capture operations, the imagingapparatus comprising: an image sensor; a vibration correction unitconfigured to correct image shake occurring due to vibration applied tothe imaging apparatus; a first vibration detection unit configured todetect and output an angular velocity of the vibration; a secondvibration detection unit configured to detect and output a displacementof the vibration based on a motion vector between two chronologicallycontinuous images from the imaging unit; a calculation unit configuredto calculate a correction value based on either the output of the firstvibration detection unit or the outputs of the first and secondvibration detection units; an output correction unit configured tocorrect the output of the first vibration detection unit using thecorrection value and to output the corrected output; and a driving unitconfigured to drive the vibration correction unit based on either theoutput of the first vibration detection unit or the output of the outputcorrection unit.
 43. An imaging apparatus including an imaging unit, animaging optical system whose imaging magnification is variable, and aninstruction unit to allow a user to instruct the image stabilizationcontrol apparatus to execute image capture preparation operations andimage capture operations, the imaging apparatus comprising: an imagesensor; a vibration correction unit configured to correct image shakeoccurring due to vibration applied to the imaging apparatus; a firstvibration detection unit configured to detect and output an angularvelocity of the vibration; a second vibration detection unit configuredto detect and output a displacement of the vibration based on a motionvector between two chronologically continuous images from the imagingunit; a calculation unit configured to calculate a correction valuebased on the outputs of the first and second vibration detection units;an output correction unit configured to correct the output of the firstvibration detection unit using the correction value and to output thecorrected output; a driving unit configured to drive the vibrationcorrection unit based on either the output of the first vibrationdetection unit or the output of the output correction unit; a principalpoint movement detection unit configured to detect and output a changeof a principal point of the imaging optical system due to a change ofthe imaging magnification; and a correction value correction unitconfigured to correct the correction value based on an output of theprincipal point movement detection unit.
 44. An imaging apparatus havingan instruction unit to allow a user to instruct the image stabilizationcontrol apparatus to execute image capture preparation operations andimage capture operations, the imaging apparatus comprising: an imagesensor; a vibration correction unit configured to correct image shakeoccurring due to vibration applied to the imaging apparatus; a firstvibration detection unit configured to detect and output an angularvelocity of the vibration; a second vibration detection unit configuredto detect and output a displacement of the vibration based on a motionvector between two chronologically continuous images from the imagingunit; a calculation unit configured to calculate a correction valuebased on either the output of the first vibration detection unit or theoutputs of the first and second vibration detection units; an outputcorrection unit configured to correct the output of the first vibrationdetection unit using the correction value and to output the correctedoutput; a driving unit configured to drive the vibration correction unitbased on either the output of the first vibration detection unit or theoutput of the output correction unit; and a reliability determinationunit configured to determine reliability of the correction value,wherein if it is determined by the reliability determination unit thatthe reliability is low, the output correction unit is configured to usea previously stored correction value to correct the output of the firstvibration detection unit.
 45. An image stabilization control apparatuscomprising: a vibration correction unit configured to correct imageshake occurring due to vibration applied to the image stabilizationcontrol apparatus; a first vibration detection unit configured to detectand output an angular velocity of the vibration; a second vibrationdetection unit configured to detect and output an acceleration of thevibration; a calculation unit configured to calculate a correction valuebased on the output from the first vibration detection unit and theoutput from the second vibration detection unit; an output correctionunit configured to correct the output of the first vibration detectionunit, the output correction unit being configured to correct the outputof the first vibration detection unit using the correction valuecalculated; and a driving unit configured to drive the vibrationcorrection unit based on the output of the first vibration detectionunit corrected by the output correction unit.
 46. The imagestabilization control apparatus according to claim 45, wherein themechanism is at least one of a mirror unit, a shutter mechanism, adiaphragm unit, or an auto-focusing unit.
 47. The image stabilizationcontrol apparatus according to claim 45, wherein the calculation unit isconfigured to calculate the correction value until immediately beforethe vibration of the mechanism occurs and is configured to suspend thecalculation of the correction value during the vibration of themechanism occurs.
 48. The image stabilization control apparatusaccording to claim 45, wherein the calculation unit is configured tocalculate an average value of the correction values calculated until thevibration of the mechanism occurs and is configured to output theaverage value to the output correction unit.
 49. The image stabilizationcontrol apparatus according to claim 48, wherein the calculation unit isconfigured to calculate the average value of the correction valuescalculated in each predetermined period and is configured to output thelatest average value of the correction value, when the vibration of themechanism occurs, to the output correction unit.
 50. The imagestabilization control apparatus according to claim 49, wherein thecalculation unit is configured to calculate and update the average valueof the correction values by a moving average method.
 51. The imagestabilization control apparatus according to claim 45, furthercomprising an imaging optical system, wherein the first vibrationdetection unit is an angular velocity meter, wherein the secondvibration detection unit is an accelerometer, and wherein the correctionvalue is equivalent to a distance from a position proximity to aprincipal point of the imaging optical system to a rotational center ofthe vibration, the distance is calculated according to a signal based onan output of the angular velocity meter and a signal based on an outputof the accelerometer.
 52. The image stabilization control apparatusaccording to claim 45, further comprising an imaging optical system,wherein the first vibration detection unit is an angular velocity meter,wherein the driving unit includes a driving coil and is configured todrive the vibration correction unit by feeding a current to the drivingcoil, and wherein the second vibration detection unit is configured todetect vibration based on the current flowing through the driving coildue to the vibration in a state in which the driving unit is not driven.53. The image stabilization control apparatus according to claim 52,wherein the vibration correction unit is used as the second vibrationdetection unit until immediately before the vibration of the mechanismoccurs.
 54. The image stabilization control apparatus according to claim45, further comprising a reliability determination unit configured todetermine reliability of the correction value.
 55. The imagestabilization control apparatus according to claim 54, wherein thereliability determination unit is configured to determine that thereliability of the correction value is low if a length of a time periodfor calculating the correction value is shorter than a length of apredetermined time period.
 56. The image stabilization control apparatusaccording to claim 54, wherein the reliability determination unit isconfigured to determine that the reliability of the correction value islow if the correction value is greater than a predetermined value. 57.The image stabilization control apparatus according to claim 54, whereinthe reliability determination unit is configured to determine that thereliability is low if the output of the first vibration detection unitis smaller than a predetermined value.
 58. The image stabilizationcontrol apparatus according to claim 54, wherein the reliabilitydetermination unit is configured to determine that the reliability islow during the mechanism is moving.
 59. The image stabilization controlapparatus according to claim 54, wherein if it is determined by thereliability determination unit that the reliability is low, the outputcorrection unit is configured to use a previously stored correctionvalue to correct the output of the first vibration detection unit. 60.An imaging apparatus comprising the image stabilization controlapparatus according to claim
 45. 61. An image stabilization controlapparatus including an imaging optical system whose imagingmagnification is variable and a mechanism which causes a vibration whenthe mechanism moves, the image stabilization control apparatuscomprising: a vibration correction unit configured to correct imageshake occurring due to vibration applied to the image stabilizationcontrol apparatus; a first vibration detection unit configured to detectand output an angular velocity of the vibration; a second vibrationdetection unit configured to detect and output an acceleration of thevibration; a calculation unit configured to calculate a correction valuebased on the output from the first vibration detection unit and theoutput from the second vibration detection unit; an output correctionunit configured to correct the output of the first vibration detectionunit, the output correction unit being configured to correct the outputof the first vibration detection unit using the correction valuecalculated before the mechanism starts to move during the mechanism ismoving; a driving unit configured to drive the vibration correction unitbased on the output of the first vibration detection unit corrected bythe output correction unit; a principal point movement detection unitconfigured to detect and output a relative change of a principal pointof the imaging optical system; and a correction value correction unitconfigured to correct the correction value based on an output of theprincipal point moving detection unit.
 62. The image stabilizationcontrol apparatus according to claim 61, wherein the mechanism is atleast one of a mirror unit, a shutter mechanism, a diaphragm unit, or anauto-focusing unit.
 63. The image stabilization control apparatusaccording to claim 61, wherein the correction value correction unit isconfigured to correct the correction value such that an accuracy ofcorrecting image shake based on the output of the output correction unitbecomes maximum when the imaging magnification of the imaging opticalsystem is maximum.
 64. The image stabilization control apparatusaccording to claim 61, wherein the second vibration detection unit islocated at the principal point of the imaging optical system when theimaging magnification of the imaging optical system is maximum.
 65. Theimage stabilization control apparatus according to claim 61, wherein thefirst vibration detection unit is an angular velocity meter, wherein thesecond vibration detection unit is an accelerometer, and wherein thecorrection value is equivalent to a distance from a position proximityto the principal point of the imaging optical system, which iscalculated according to a signal based on an output of the angularvelocity meter and a signal based on an output of the accelerometer, toa rotational center of the vibration.
 66. The image stabilizationcontrol apparatus according to claim 61, further comprising areliability determination unit configured to determine reliability ofthe correction value.
 67. The image stabilization control apparatusaccording to claim 64, wherein the reliability determination unit isconfigured to determine that the reliability of the correction value islow if a length of a time period for calculating the correction value isshorter than a length of a predetermined time period.
 68. The imagestabilization control apparatus according to claim 64, wherein thereliability determination unit is configured to determine that thereliability of the correction value is low if the correction value isgreater than a predetermined value.
 69. The image stabilization controlapparatus according to claim 64, wherein the reliability determinationunit is configured to determine that the reliability is low during themechanism is moving.
 70. The image stabilization control apparatusaccording to claim 64, wherein if it is determined by the reliabilitydetermination unit that the reliability is low, the output correctionunit is configured to use a previously stored correction value tocorrect the output of the first vibration detection unit.
 71. An imagingapparatus comprising the image stabilization control apparatus accordingto claim
 61. 72. An image stabilization control apparatus including amechanism which causes a vibration when the mechanism moves, the imagestabilization control apparatus comprising: a vibration correction unitconfigured to correct image shake occurring due to vibration applied tothe image stabilization control apparatus; a first vibration detectionunit configured to detect and output an angular velocity of thevibration; a second vibration detection unit configured to detect andoutput an acceleration of the vibration; a calculation unit configuredto calculate a correction value based on the output from the firstvibration detection unit and the output from the second vibrationdetection unit; an output correction unit configured to correct theoutput of the first vibration detection unit, the output correction unitbeing configured to correct the output of the first vibration detectionunit using the correction value calculated before the mechanism startsto move during the mechanism is moving; a driving unit configured todrive the vibration correction unit based on the output of the firstvibration detection unit corrected by the output correction unit; and areliability determination unit configured to determine reliability ofthe correction value, wherein if it is determined by the reliabilitydetermination unit that the reliability is low, the output correctionunit is configured to use a previously stored correction value tocorrect the output of the first vibration detection unit.
 73. The imagestabilization control apparatus according to claim 72, wherein themechanism is at least one of a mirror unit, a shutter mechanism, adiaphragm unit, or an auto-focusing unit.
 74. The image stabilizationcontrol apparatus according to claim 72, wherein the reliabilitydetermination unit is configured to determine that the reliability islow during the mechanism is moving.
 75. The image stabilization controlapparatus according to claim 72, wherein the reliability determinationunit is configured to determine that the reliability of the correctionvalue is low if the correction value is greater than a predeterminedvalue.
 76. The image stabilization control apparatus according to claim72, wherein the reliability determination unit is configured todetermine that the reliability is low if the output of the firstvibration detection unit is smaller than a predetermined value.
 77. Animaging apparatus comprising the image stabilization control apparatusaccording to claim
 72. 78. An imaging apparatus including an imagingunit and a mechanism which causes a vibration when the mechanism moves,the imaging apparatus comprising: a vibration correction unit configuredto correct image shake occurring due to vibration applied to the imagingapparatus; a first vibration detection unit configured to detect andoutput an angular velocity of the vibration; a second vibrationdetection unit configured to detect and output a displacement of thevibration based on a motion vector between two chronologicallycontinuous images from the imaging unit; a calculation unit configuredto calculate a correction value based on the output from the firstvibration detection unit and the output from the second vibrationdetection unit; an output correction unit configured to correct theoutput of the first vibration detection unit, the output correction unitbeing configured to correct the output of the first vibration detectionunit using the correction value calculated before the mechanism startsto move during the mechanism is moving; and a driving unit configured todrive the vibration correction unit based on the output of the firstvibration detection unit corrected by the output correction unit. 79.The imaging apparatus according to claim 78, wherein the mechanism is atleast one of a mirror unit, a shutter mechanism, a diaphragm unit, or anauto-focusing unit.
 80. The imaging apparatus according to claim 78,wherein the calculation unit is configured to calculate the correctionvalue until immediately before the vibration of the mechanism occurs andis configured to suspend the calculation of the correction value duringthe vibration from the mechanism occurs.
 81. The imaging apparatusaccording to claim 78, wherein the calculation unit is configured tocalculate an average value of the correction values calculated until thevibration of the mechanism occurs and configured to output the averagevalue to the output correction unit.
 82. The imaging apparatus accordingto claim 81, wherein the calculation unit is configured to calculate theaverage values of the correction values calculated in each predeterminedperiod and configured to output the latest average value of thecorrection value, when the vibration of the mechanism occurs, to theoutput correction unit.
 83. The imaging apparatus according to claim 82,wherein the calculation unit is configured to calculate and update theaverage value of the correction values by a moving average method. 84.The imaging apparatus according to claim 78, further comprising areliability determination unit configured to determine reliability ofthe correction value.
 85. The imaging apparatus according to claim 84,wherein the reliability determination unit is configured to determinethat the reliability of the correction value is low if a length of atime period for calculating the correction value is shorter than alength of a predetermined time period.
 86. The imaging apparatusaccording to claim 84, wherein the reliability determination unit isconfigured to determine that the reliability of the correction value islow if the correction value is greater than a predetermined value. 87.The imaging apparatus according to claim 84, wherein the reliabilitydetermination unit is configured to determine that the reliability islow if the output of the first vibration detection unit is smaller thana predetermined value.
 88. The imaging apparatus according to claim 84,wherein the reliability determination unit is configured to determinethat the reliability is low during the mechanism is moving.
 89. Theimaging apparatus according to claim 84, wherein if it is determined bythe reliability determination unit that the reliability is low, theoutput correction unit is configured to use a previously storedcorrection value to correct the output of the first vibration detectionunit.
 90. An imaging apparatus including an imaging unit, an imagingoptical system whose imaging magnification is variable, and a mechanismwhich causes a vibration when the mechanism moves, the imaging apparatuscomprising: a vibration correction unit configured to correct imageshake occurring due to vibration applied to the imaging apparatus; afirst vibration detection unit configured to detect and output anangular velocity of the vibration; a second vibration detection unitconfigured to detect and output a displacement of the vibration based ona motion vector between two chronologically continuous images from theimaging unit; a calculation unit configured to calculate a correctionvalue based on the output from the first vibration detection unit andthe output from the second vibration detection unit; an outputcorrection unit configured to correct the output of the first vibrationdetection unit, the output correction unit being configured to correctthe output of the first vibration detection unit using the correctionvalue calculated before the mechanism starts to move during themechanism is moving; a driving unit configured to drive the vibrationcorrection unit based on the output of the first vibration detectionunit corrected by the output correction unit; a principal point movementdetection unit configured to detect and output a relative change of aprincipal point of the imaging optical system; and a correction valuecorrection unit configured to correct the correction value based on anoutput of the principal point movement detection unit.
 91. The imagingapparatus according to claim 90, wherein the mechanism is at least oneof a mirror unit, a shutter mechanism, a diaphragm unit, or anauto-focusing unit.
 92. The imaging apparatus according to claim 90,wherein the correction value correction unit is configured to correctthe correction value such that an accuracy of correcting image shakebased on the output of the output correction unit becomes maximum whenthe imaging magnification of the imaging optical system is maximum. 93.The imaging apparatus according to claim 90, further comprising areliability determination unit configured to determine a reliability ofthe correction value.
 94. The imaging apparatus according to claim 93,wherein the reliability determination unit is configured to determinethat the reliability of the correction value is low if a length of atime period for calculating the correction value is shorter than alength of a predetermined time period.
 95. The imaging apparatusaccording to claim 93, wherein the reliability determination unit isconfigured to determine that the reliability of the correction value islow if the correction value is greater than a predetermined value. 96.The imaging apparatus according to claim 93, wherein the reliabilitydetermination unit is configured to determine that the reliability islow during the mechanism is moving.
 97. The imaging apparatus accordingto claim 93, wherein if it is determined by the reliabilitydetermination unit that the reliability is low, the output correctionunit is configured to use a previously stored correction value tocorrect the output of the first vibration detection unit.
 98. An imagingapparatus including an imaging unit and a mechanism which causes avibration when the mechanism moves, the imaging apparatus comprising: avibration correction unit configured to correct image shake occurringdue to vibration applied to the imaging apparatus; a first vibrationdetection unit configured to detect and output an angular velocity ofthe vibration; a second vibration detection unit configured to detectand output a displacement of the vibration based on a motion vectorbetween two chronologically continuous images from the imaging unit; acalculation unit configured to calculate a correction value based on theoutput from the first vibration detection unit and the output from thesecond vibration detection unit; an output correction unit configured tocorrect the output of the first vibration detection unit, the outputcorrection unit being configured to correct the output of the firstvibration detection unit using the correction value calculated beforethe mechanism starts to move during the mechanism is moving; a drivingunit configured to drive the vibration correction unit based on theoutput of the first vibration detection unit corrected by the outputcorrection unit; and a reliability determination unit configured todetermine reliability of the correction value, wherein if it isdetermined by the reliability determination unit that the reliability islow, the output correction unit is configured to use a previously storedcorrection value to correct the output of the first vibration detectionunit.
 99. The imaging apparatus according to claim 98, wherein themechanism is at least one of a mirror unit, a shutter mechanism, adiaphragm unit, or an auto-focusing unit.
 100. The imaging apparatusaccording to claim 98, wherein the reliability determination unit isconfigured to determine that the reliability is low during the mechanismis moving.
 101. The imaging apparatus according to claim 98, wherein thereliability determination unit is configured to determine that thereliability of the correction value is low if the correction value isgreater than a predetermined value.
 102. The imaging apparatus accordingto claim 98, wherein the reliability determination unit is configured todetermine that the reliability is low if the output of the firstvibration detection unit is smaller than a predetermined value.